Composers are one of the easiest team members to find. If you place an ad on Craigslist, you'll be bombarded with replies - from experienced ones, to those looking to do their first attempt at someone else's material.
Their location doesn't matter that much, as audio files are small enough to email many times (or using free RapidShare, if large).
Here's what I did on my last project:
1) Added a visible timecode burn to film (optional but extremely useful)
2) RapidShare'd a 360x240 quicktime file of the film
3) RapidShare'd a 360x240 quicktime file - with the notes on it! Using the "Title" tools, put a description of the type of music/ambience needed for that particular stretch. All kinds of notes can be put on here. Just place the titles on the areas they cover.
If you want, you can also lay down a temp track - ie: put that Batman track where you need that music. Composer then hears & sees exactly where the soon-to-be-created batman-esque music needs to go.
4) Wait a week.
5) Receive music file(s) and place into your timeline. If you were able to generate that timecode burn, the composer ought to send you a cue list, as well, that lists the exact points to drop the various files in at.
6) Winnah!
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In your Craigslist ad, be sure to put in all relevant details for payment (even if it's none!) so you don't waste anyone's time. Also, ask for any replies to link to their website or sample tunes. Even composers who've never had a real gig ought to have a website, with sample tracks on it.
Spend a few days going through all the replies & links, then get in contact with the one you like best.
Good luck!