Post 1,000!
Need music or sound effects? Here's the resource topic for existing MIDI, MP3 and WAV downloads. Remember, you cannot use MIDI files in Flash, so you'll need to convert them yourself. There are plenty of ways to do this - either manually or with software programs.
MUSIC
http://remix.overclocked.org/index.php
http://www.ifni.com/
http://www.sunncity.com/music/
http://billbrownmusic.com/musicmain.htm
http://www.freeplaymusic.com/
http://www.mididb.com/
http://www.gamingw.net/music/
http://www.vgmusic.com/
http://www.soundtempest.net/music.html
http://www.technomidi.com/
http://www.royaltyfreemusic.com/free-music-resources.html
http://www.flashkit.com (Also contains SFX)
SFX
http://www.sounddogs.com/start.asp
http://www.a1freesoundeffects.com/
http://www.grsites.com/sounds/
Specific game music sites:
Nintendo
http://www.megaone.com/dannyone/ssbm_download.html
http://cube.smedia.co.uk/downloads/music.htm
http://www.classicgaming.com/tmk/sounds.shtml
http://www.snesmusic.org/spcsets/
Megaman
http://www.angelfire.com/pq/MegaManMusic/
Sonic
http://www.sonicunited.com/music.php
http://www.planetdreamcast.com/sonic/listen/index.html
Doom
http://www.doomworld.com/music/
More? Post them!