hey! if they're grime ogg files you got off me on soul seek, its a condition of downloading that you appreciate the format...
ogg is smaller file size for the same sound quality as mp3. plus its a genuinely free codec unlike mp3. you can get the ogg codec from the
ogg vorbis website and that'll let you play em in itunes or where ever...
i spose you might want mp3s to put on your ipod if they dont support ogg... the GPL tools for doing the conversion would be oggenc (ogg encoder) and lame (Lame (is not) An Mp3 Encoder) you can get them on linux or mac using the packaging tools... yum or apt or whatever the mac one is called. or go to sourceforge i guess for windows builds.