Similarly to master131's old releases for MW2 and MW3, I decided to figure out how to extract sounds from the COD4 fast files. The format is exactly the same, interestingly enough.
With some help by him to figure out the header structure fully, here is the full archive with all wave sounds found in all COD4 PC fast files, with proper RIFF headers, correct channel number and samplerate. Or at least all I could find by simply searching for .wav ;)
Oh, and one more thing: The playback speed/pitch is different in the game for some files. Refer to the soundaliases in the mod tools to figure out how much slower the file (or faster) is actually played ingame (for example the AC130 105mm fire sound is much slower ingame than the source wav file is).
The rest of the sounds is available via easy extraction from the iwd files and the mod tools.
Like him, I uploaded it to google drive since it's larger than this forum would allow for attachments (the archive contains only wav files):
https://*************.com/file/d/0B00...gwT0ZESHIxbzQ/
Remember though, these files are the intellectual property of Infinity Ward, Activision etc, so don't use them for anything except creating mods for COD (they don't seem to care about that).
Enjoy!