I haven't had a chance to try out code snippets yet but I've found a couple of other people blogging about them

http://blogs.msdn.com/jamesnewkirk/archive/2004/06/02/147153.aspx

http://jasonkemp.ca/archive/2004/07/18/197.aspx

And a good article by O'Reilly http://www.ondotnet.com/pub/a/dotnet/2003/12/01/whidbeysnippets.html