SQL Server 2005 SP2 released to the web today. You can find it here: http://www.microsoft.com/sql/sp2.mspx
Note that the serivce pack does not update the samples. You'll need to download the updated samples separately from here: http://www.microsoft.com/downloads/details.aspx?familyid=e719ecf7-9f46-4312-af89-6ad8702e4e6e&displaylang=en. There is a link from the SP2 page to this samples download. Be sure to delete and then uninstall old sample databases before installing the new ones.
There are a lot of bug fixes in this web refresh of the samples, plus there are several new samples. There are five new samples too. The information on the new samples, and all the old ones is in the samples readme file here: http://download.microsoft.com/download/d/8/6/d865cf0c-c44b-401b-b426-b3bf5c628112/SQLServerDatabasesAndSamplesOverview.htm
There is also a new member of the AdventureWorks family of sample databases, AdventureWorksLT. This is a highly simplified and somewhat denormalized version of the Adventure Works OLTP database focused exclusively on a simple sales scenario. There will be more information about this latest member of the sample database family soon.