This blog post has been replaced by a newer one that covers both TFS 2005 and TFS 2008: http://blogs.msdn.com/bharry/archive/2008/01/15/checking-your-tfs-version-and-extending-trials.aspx
People seem to still be having issues with trials. Some are because they forget to purchase a licensed copy before the trial expires and some have ...
We've been working on putting together docs on 4 SP1 features. The documentation team will be ultimately releasing it through MSDN online docs updates but until then, it will be released through blogs.
Enjoy!
Brian...