After installing SP2 on my development MOSS machine, I was unable to load the Central Administration site.  By disabling custom errors and enabling the callstack in the Central Admin web.config file, I found out why I was having the issue.

The web application could not load assembly “Microsoft.Internal.Mime, Version=8.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35”.  The following web.config file was the culprit: C:\Program Files\Common Files\Microsoft Shared\web server extensions\12\TEMPLATE\ADMIN\web.config

After checking the GAC, I noticed that there was a newer version of this assembly that SP2, see http://support.microsoft.com/default.aspx/kb/970359.

Using Reflector, I copied the updated Name and updated the web.config file. 

Central Admin on my dev box is now working again.  I suppose I could dig through the SP2 installation log to see if I can find out why this didn’t update…