Isohunt provides users with access to a massive number of files that are free to download as long as you have a torrent download program such as Utorrent. Isohunt is a great site so long as it is used with care. The content is all posted by isohunt's community and consequently a certain number of virus infected files are inevitable. To avoid downloading one of these I would reccomend only downloading files that have received positive comments by members of the isohunt community. Generally the community is very good with this. If a file has no comments just don't download.
Aside from that small proviso the site is excellent and is the best torrent download site I have come across. One more point is that I have heard that certain authorities are planning to clamp down, or already are doing, on sites like isohunt for allegedly posting illegal content but talk like that has been around for years in regard to number of sites and the only big one that ever really got hit was Napster.