Torrent is a small file (around few kilobytes) with the suffix .torrent, which contains all the information needed to download a file the torrent was made for. That means it contains file names, their sizes, where to download from and so on. You can get torrents for almost anything on lots of web sites and torrent search engines
So far, uTorrent 1.8 is the best torrent version ever. It's light and fast and there have been great improvements as far as features (such as the icon and user interface) and performance are concerned.