It occured to me when I posted about Peerblock that I neglected to post about a very useful site in regards to it’s use; that site is I-BlockList. It’s a really simple site with some of the most popular services IP ranges there so you can be sure you’re blocking (or allowing) specific things through. For example I play games on Steam and there is a Steam list so I can access the services.
So head on over to the site and grab your block lists, whether you use Peerblock or Peerguardian or any other software that supports the lists for that matter!