Ok, how to get uk football streamed to your xbox. You need sopcast installed and running on a pc on your home network. You need a file on your xbox in a location where xbmc will see it. The file is a text file - i've named mine sopcast.m3u. Contents of the file are;
Edit it for your pc's ip address obviously and if you're using a recent copy of sopcast the port should be correct. Older sopcast versions use 8900.
On the pc, find a stream to watch. For UK football you should be able to find a sopcast stream from;
http://www1.myp2p.eu/competition.php?competitionid=&part=sports&discipline=football or http://www.engfootball.com/
Once it's running on the PC, switch over to your xbox. Load up xbmc (you have got it installed as the dashboard right?) and add a source which points to the folder containing the m3u file. Click the sopcast.m3u and you're away.