Well, I can only say the things that I have done. My experiences have only happened in Chicago and Dallas. In Chicago I attended an Adventures in Voice Acting class where I was able to network with a lot of the other students and thus found out about some websites and projects I wouldn't have otherwise. I highly recommend the classes too, they are extremely beneficial and educational. In fact, they are having more classes in Chi-town in about two weeks if you can manage, maybe I'll see ya?
When I was in Dallas, I visited multiple gaming studios and animation houses and simply talked to the secretary and got the information needed in regards to emailing casting director and getting on their mailing list about auditions.
Past that, network, network, network.