Hiya Gopher.
As for me, I go about it one of several ways.
I have several musically oriented friends, including a few people I know through other friends of mine who compose their own music... lucky for me they have an interest in film and are willing to do it for free.
Also, and my latest musical venture, included licensing a song for a festival license. Ended up working, and I managed to work myself out a good deal in the process. All together, the license was about 300 bucks, the fee I paid to Evan M Greenspan Inc. to discover who owned the synch rights was another 80 bucks, then the money I spent UPS-ing checks & license copies totaled around another 60 dollars (though I overnighted things to expedite the process)... and in the end I have a music license that allows me to distribute my short film to film festivals world wide and on the internet (non-downloadable content)... the film will be premiering on my website in the next few hours when I've re-created the non-downloadable streaming file and uploaded it.
Anyhow...
there's also the route of finding royalty free music... but honestly, that is usually the crappiest music I've ever heard... everything sounds like the evening news... lol... which can be good if that's what you need.
Well, good luck with the music... and if you think you'd like to find yourself a free composer... try posting on Mandy or other job sites that allow free posting.