If you want to get into a band, you have to make an impression. Karaoke is a great way to gain confidence, but I must caution you to NEVER EVER use the "K-word" when you're talking to a "real musician." That can get you shot down in a heartbeat. Once you have a little confidence, start showing up at open jams in your area. Get to know some of the local players. Get up there & show your stuff. If you have any friends that have bands, see if you can sit in for a song or 2 at a small show. Get your face & voice out there. Learning an instrument (or at least a few songs on guitar) will really help. I found a great site called www.ultimate-guitar.com
that has tons of guitar tab & chords. It has a great feature for beginners; when you mouse over the chord on the song, the chord diagram will appear. Check your local paper; many have musicians' classified ads for bands seeking members. I found my first band that way.
As far as gear goes, you should at the very least have your own mic. It doesn't have to be the most expensive one on the market; Shure SM58 is pretty much the industry standard, & will run you about $100. Get at least a 25' cable, or you'll be back at the music store getting another one. If you can get a full PA, go for it! Musician's Friend ( www.musiciansfriend.com
) has some good deals on PA packages. Also, check the local pawn shops. Used gear can insinuate experience, where brand new stuff can give the impression that you're a newbie.
Once you have an auition, don't say you're a "band virgin" unless asked. Let your stage presence speak for you. Remember, performance is just as much about the image you portray as the music itself. Don't be an arrogant jerk, but don't be timid, either. Have confidence, sing your ass off, & you'll be in there before you know it! Good luck!
PS: I got a late start, too. I joined my first band in my early 30's, & haven't looked back!