Many pirated movies, music and tv series are illegally available for download but, the software itself is perfectly legal. After all, if you emailed a video clip from a tv series to your friend, would that mean that Outlook Express could be banned?

But this kind of software can get people into a lot of trouble. A recent case had young children being arrested for allegedly illegally downloading music. Another case in Australia had someone fined for linking to illegal download sites.

Bittorrent, though, is used quite legally to trade home videos and independent music publicity programs (Indie). It's also used to transfer university documents and other large files. If you're looking for a way to freely download large files with less chance of the file becoming corrupted, Bittorrent is the way to go.

There are various free programs available for download on the internet. The cross platform systems are the best as that usually means more seeders. 

The best free cross platform torrent clients include:
Bittorrent (the original)
ABC (Yet Another BitTorrent Client)
Azureus - Very good but resource hungry. Make sure you have a fast computer with lots of ram. 
BitTornado 

Others include:
BtManager 
Rufus 
XBT Client 
Anatomic P2P 
TorrentFlux 

ABC is probably the best overall due to its ease of use but UTorrent, a new torrent client with a small footprint, has recently taken it on. If you have a lot of RAM and a fast computer, you may wish to try Azureas as it is the most feature rich torrent available.

So, why not Kazaa?
Kazaa worked by connecting to one file and continuing to download that file bit by bit from one or two people whenever their computer was on. Bittorrent works by connecting to various available parts of the file worldwide and assembling them at the same time as making complete parts available for others to download. Then, when all parts are downloaded you get a complete file. As a result, 5 Gigabyte files or more are regularly traded online.

So how can I download files via Bittorrent?
Firstly, choose the program you want to use and install it on your computer. Just search via Google for 'bittorrent clients' and you're sure to find some.

Then, if there is a particular file that you want to download (maybe a friend has seeded their personal travel video) you can connect to the file and start downloading.

Torrent Search Engines
And, if you don't know what that file address is, you may wish to use a torrent search engine to find it.
Here are some useful engines:
 

Have fun!