Hang around music stores like guitar center, put up flyers there saying you want to start a band "contact *so and so* number". It's not that uncommon to just find people you don't really know. Black Sabbath was started out of a yellow pages ad I think. It may have just been Ozzy though, I think he put in an ad for himself as a hard rock singer and Sabbath called him.
But yeah, he can put up flyers or start going to the guitar center and just playing guitar for a couple of hours. It's sort of an investment. A bunch of musicians will hear you just jamming in the lobby, and if they like what they hear they'll probably try to start a conversation.
I can't really think of anything else. Myspace and Facebook I guess. If theres any clubs around that play lots of live music you can put up flyers there too with contact info. Flyers with contact info is the best thing I can come up with. It's sort of hard to just find musicians because they don't exactly always propogate that they play instruments. It's somewhat of a luck thing.
Thats one of the reasons I want to go to a music college. Networking.
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