Well today I came across it for fairly cheap and bought the game. Skyrim is what actually pulled me into TES games, so I felt like I knew what I was doing. Instinctively I chose what I was in Skyrim: A Nordic Warrior with Light Armor with a Sword-Shield combo.
Fought my way out of that dungeon, and finally found myself outside the Imperial City. In other words, I am enjoying this game so far.
1. In Skyrim I earned money through completing dungeons and looting fallen bodies. How should I go about getting money in Oblivion?
2. Am I high enough level (level 1...) to start doing the main quest, or should I do some of the Guild's stuff first?
3. Where do I view my perks?
4. Is Cyrodil larger or smaller than Skyrim?
5. Any tips or advice you'd like to give me? Ways I should go about leveling, getting gold, when and where to buy better equipment, etc...

There are skill advances, and at Apprentice (25) Journeyman (50), Expert (75) and Master (100) the game allows us new things our characters can do. We don't get a choice with these, though, like we do with Sky's perk system.
In this respect, both Oblivion and Skyrim are the same.
Here, I'll put it in spoiler tags, just in case the OP wants it to be a surprise.
All the bandits who just a few days ago could only be found wearing furs and leather? Well now they're