
BitTorrent is a method for sharing large files that reduces the amount of bandwidth needed. This technology is what makes it possible for SXSW to offer a download of every sample track for bands that will be playing at SXSW06. You can learn more about bit torrent here.
To get all this great music and video, you will need to download a BitTorrent client, such as Azureus (free). Once you have a client installed, download one of the torrent files above, and open it with the client. If you've installed Azureus, you can find detailed instructions here.
Once the download is complete, you can drag the download directory into iTunes, and iTunes will import all the songs into your music library. But since BitTorrent works by sharing the bandwidth of everyone who has downloaded this music, please leave your client running until you have uploaded at least as much data as you downloaded. Many clients will display your sharing ratio, which makes it easy to know if you've "paid back" the bandwidth you used to download the music.