I have recently been posting narratives of specific in-game events, including part of the main quest.
I described how you find out the identity of the black dragon who interrupted your execution and is going around reviving dead dragons, as well as the first encounter with one of the last Blades (who were famous for protecting the Emperor, but originally started out as renowned dragon-slayers), and the apparent hierarchy within the Vampire faction (there are non-vampiric serfs in it too).

Now, for those who are still wondering about how exactly werewolves first appear to the player, here follows a step-by-step walkthrough and SPOILER:

Soon after joining the Companions, you are given a seemingly simple but meaningful quest. The guild has received a tip from a scholar reguarding the location of one of the fragments of Wuuthrad, the blade weapon that once belonged to the very founder of the Companions. If you succesfully complete this quest, you will be inducted.

Your shield-brother (companion) is a strong and simple warrior named Farkas. He will keep an eye on you to see if you can prove yourself as a worthy Brother or Sister. If you still have Lydia (a follower appointed to you by the Jarl of Whiterun) with you, she is replaced by Farkas and returns home.

The location for this quest is Dustman's Cairn. It's an ancient, underground burial site so it's full of creepy undead foes. Upon entering, Farkas remarks that there are traces of recent digging. Make your way through the underground passages, killing mostly Draugr and Restless Draugr, until you reach a larger room with a lever in a hollowed out corner.

Curiousity killed the cat:

Pull the lever and a barred metal door shuts you in. The lever is now stuck. You are effectively trapped, much to the annoyance of Farkar. Just as he goes to find you a way out, he is ambushed by members oif The Silver Hand. He is greatly outnumbered and all you can do is watch helplessly from behind the gate. He doesn't seem too worried though:

Silver Hand: "Killing you will make for an excellent story."
Farkar: "None of you will be alive to tell it."

Yes, this is where it happens: letting out a beastly cry, he morphs into a werewolf until he towers two or three heads above the rest. With is enormous claws, he easily massacres the whole lot of them in a matter of seconds, then quickly runs off to find the release for your trap.

When he returns, he is human again and you can ask him about what just happened. He tells you about his "gift" and reveals to you that within The Companions, all those who are part of "The Circle" are werewolves too. If you wish to receive "beastblood" you will have to climb your way up the ranks of the guild.

The Silver Hand, he explains, are werewolf hunters who seem to know about the Companions' secret.There are many more of them up ahead, throughout the rest of the burial site, as well as more Draugr.

Thank you. I appreciate this

Unlike the comments you'll get from some people who browse spoiler forums and yet [censored] there's too many spoilers , I appreciate learning these details!

Thank you it makes sense now!

It will be interesting to see if there are any downsides to joining the Circle. Random Silver Hand attacks while traveling perhaps? Townsfolk who will shun you because they know your secret?

What if you want to advance in the guild without having to become a werewolf? :S

Im sure thatll be an option.

Yep. In Oblivion you could receive the "Dark Gift" if you joined the Dark Brotherhood, as a reward for completing quests. It was offered by a vampire in the Dark Brotherhood as an option. I believe this will be the case in Skyrim with The Circle.

That's possible. In Oblivion you were sometimes randomly assaulted by members of the Mythic Dawn for helping Martin Septim.

In human form you can hardly tell they're werewolves, but in Bloodmoon everyone was absolutely terrified of you in beast form so probably shouldn't morph in public.
I'm sure it's much easier on your social interactions than being a vampire, which in Oblivion and Morrowind was always obvious to everyone and did lower peoples' disposition towards you.

Op is spot on. Good thing we can get involved at the start too. Also, sorry if i just posted in someones profile lol, i am using cellphone on a bus.

i noticed he talked while he was in werewolf form, that shows how he really was in control at the time.

That's right, he said "Good enough" as he slayed the last one of them, still in his beast form.

And it was definitely a voluntary transformation

Okay, Falkar just won +50 badass points from me with that line.

Just a question, you can recruit Lydia again if you wished, right? Dump Falkar back in his base and go grab Lydia?

This, I would also like to know. I was under the impression that multiple companions could be recruited at the same time.

A Companion named Aela offers you her blood as part of a ceremony, but you are free to decline. You are not forced into lycanthropy - it's completely optional.

All of the Silver Hand warriors had silver swords, so that's very likely.

OMG! this sounds awesome... way better than I expected Lycanthropy to be, just some disease you could catch if the were-creatures hurt you. Can't wait now... anticipation is at an all time high.

I only hope that you're also able to join or help the Silver Hand if you so wish. I sorta wanted to roleplay a monster hunter character that would take down werewolves, giants, vampires, witches, pretty much any beast creatures...

That's cool that you can choose but first i gotta play as one

Does she offer her blood or does she "offer her blood"?

This is awesome, next friday can't get here fast enough!!

Hopefully there will be more ways than just this to become one. Obviously there will be, I mean i doubt they would force you to join a guile in order to become one.
Honestly its gonna be one of the few things I look up day one to find out where I could possibly go. I mean this is one of the few things I think would get put up fast enough. Won't read the how though, just the where, don't wanna spoil it too much.

Epic...I cannot wait...Thank you for the description BT9's...

LOL so the silver hands are quintessentially the Ghostbusters of Skyrim?? Wow im thoroughly impressed. Ok so im sorta a svcker for details so i wanted to know:

1. Exactly how did the transformation look? Was it like a magical glow came around him and he instantly was a werewolf or was it more like he was busting out of his clothes and u see his body slowly go from human to dogish?

2. Where are the Companions headquartered? Like exactly where do u find them, in a city or some clandestine locale?

For the sake of not getting flamed you can add the answer to these questions in the form of spoiler tags or you can just pm me whichever you perfer...lol i feel like a prisoner writing letters to his bff on the outside trying to keep up with the goings on of life

This sounds interesting.

The Companions are in a town/city, I believe. I think they're centered around Winterun.

STOP!
You violated the law!
Pay the court a fine or serve your sentence!
Your stolen goods are now forefit!

yeah im quite interese game is out
till thted in these videos but well its not that long

yeah im quite interested in the vids myself