(i.e. amount of kbs)
Limeware is very good but you need to get limeware pro (which is not free, but also downloadable if you do a google research on "utorrent") and anything in the region of 2,000kb upwards is likely to be a song, but files with just 3 figures or less (***kb) are likely to be a virus/spyware.
I also heard about Kazaa.com but I don't know how good it is
i wouldn't go near kazaa in this day & age. it is full of spywares and you're likeky to have the copyright people knocking on your door wanting compensation.
mostly older, but that's what I wanted... :)
can't beat old skool!
utorrent dot com