Nice looking introductions and such for those wanting a way in to this http://docs.jquery.com/Tutorials
and here is Jan Tielens - every reliable intro to jquery and sharepoint
http://weblogs.asp.net/jan/archive/2008/11/20/sharepoint-2007-and-jquery-1.aspx
and those nice people at endusersharepoint have some pretty cool stuff too
http://www.endusersharepoint.com/?p=1075
