The time-honoured way: Go to your local music store (the one that sells guitars, amps and drums) and check if they have a bulletin board. You can find postings from bands looking for members or musicians looking for bands, or post your own. If there are any good, local record stores--by which I mean the ones that stock local/indie/underground CDs and vinyl and have knowledgeable and passionate staff, not the bigbox chain--they might also have a bulletin board. You can also try Kijiji, Facebook or other websites.
If there's a local music scene friendly to the kind of music you want to play, try to get involved in it: go to shows, make friends with other bands, and maybe ask people at the clubs if they or someone they know wants to jam.
Go to open mic nights. All you need is a guitar and some songs under your belt, and usually you can play mostly or all covers. You get used to playing in public and you might find someone else whose musical skill or songwriting you like and you can potentially pick up a bandmate or two that way. And redblinky has an excellent point: unless you are a really awesome songwriter, it really helps to have at least one other brain to bounce ideas off of.
Try to jam with as many people as you can, and learn as many songs as you can. And I mean complete songs from beginning to end. You'd be surprised how many people say they can play guitar and only know a handful of riffs from here and there.
I'm a bass player, and it pains me to say this, but most songs can get away with having simple basslines. Find an enthusiastic friend who's willing to shell out for a cheap bass and amp (you can buy those package deals in music stores for $200 or less), and teach them how to play basic basslines. Then all you really need is to find a drummer (good luck!).
