Well, earlier today I received the quest "Go speak to Lod" so I can start "A Daedra's Best Friend." However, once I got to Falkreath, Lod was already dead from a dragon attack. I've heard that Barbas wanders around Falkreath, however does anyone have any other specific tips on how to catch him?

According to the wiki the pup will still be around even if Lod is no longer alive. The last few times I did this, he was on the road leading left from the T-intersection just outside of town, but your mileage may vary. He IS annoying, not for talking, but because he tends to push you instead of leading, and can even force you off cliffs or narrow walkways by accident (sure, sure, Bethesda, it's an accident, I understand). http://www.uesp.net/wiki/Skyrim:A_Daedra%27s_Best_Friend

Sweet. Thank you for the help, I'll go look for him after work today.

So I've spent about an hour of real time wandering around Falkreath, and I still can't find that dog. However, I noticed in the link that if " Lod is dead before you can talk to him about the quest, Barbas doesn't come. Instead his statue will still be at the shrine of Clavicus Vile and the quest (which is still given by the guards) can never be finished. PC-users may be able to bypass this with console commands."

Does this mean I can't find the dog?

Pretty much. Lod was supposed to give you some meat to attract the dog. Without it, he doesn't show up.

you don't need meat, I have done the quest three times never used or recieved any meat from Lod, Lod might need to be alive, on that I am not sure.

Im having the same problem--if you know a solution would be grateful for some help

With my games he's been a little ways outside of town (in direction of Helgen), but not as far as that bridge-type bandit lair.
He's easy to miss if he's a little ways off as he blends into the road, did you venture far enough?

OT, the Barbas VA reminds me so much of the character actor from the 60s, Ed Wynn.