Divx Site - Important if you are going to view any of the files.
The "org" - This is the "HOME" page of any and all things to do with AMV's. There are posts of contests, info on how to begin creating, as well as a database with most on the AMV's out there.
This site is a database with a list of all the biggest Convention contests in the last few years. It includes links to each contest and the participants as well as links to the video themselves where applicable.

Anime Boston - This is the Convention that started it all for me. It began in 2003 and has increased every year to the point that it's now hosted at the Hynes Convention Center. Last year they had 89 submissions with 30 finalists in the AMV contest.
Anime Weekend Atlanta. One of the premiere contest hosts in the east coast. Three different contests within the con itself with over 300 submissions.
Yes, there are Llamas in the anime community. This is a smaller one-day con for fans, by fans in Great Barrington, Mass. This was a very fun experience as it was the first time they did this con and, to my enjoyment, far surpassed all expectations in the "FUN" department. A true con for the artists.
The store I frequent. You'll find me there at least a couple of days a week.