I got involved with a band by participating in a program at a local guitar store called "Adult Rock Band". It's been a year and the band is still going, though I had to leave due to time constraints. School of Rock has similar programs.

Another option is to put yourself out on bandmix.com. You can also search bandmix.com for people looking to jam.

Are there any open mics in your area? Around there, they have some at music stores, not just bars. I've been to a few and it's really fun to rub elbows with fellow musicians.