Limewire and Frostwire are not 'sites'. They're programs which enable you to download files from other people's PCs. They both use the Gnutella network, so you'll find the same downloads available with either program.
If you're looking for a program which uses a different network (eDonkey), you might want to try Shareaza. (eDonkey was officially closed down 4 years ago but the network is still functioning).
Some people prefer using the BitTorrent protocol, which utilise programs like BitComet.
However, you need to remember that it's a civil offence (for which you can be sued) to
download copyright material without permission but all peer-to-peer programs work on the basis that you also make files available for sharing. That counts as 'distribution', which is a
criminal offence (for which you can be fined or imprisoned).
Your 'free' file transfers could end up costing you around $80,000 per track:
http://news.bbc.co.uk/newsbeat/hi/technology/n ewsid_8108000/8108589.stm
Chris