I came across this a while ago and forgot to post… James Shore is putting together what basically looks like a “how to get agile” guide. The book chapters are posted fairly frequently for review. Looks like a good read.

http://www.jamesshore.com/Agile-Book/

Updated - See http://www.pksoftware.net/blog/2007/02/06/Getting+Started+With+NUnitForms.aspx

I have not had a huge look at this yet but a not so known spin off from NUnit:

http://nunitforms.sourceforge.net/

Unit testing geared towards .Net WinForms applications...