All the sample data bases including AdventureWorks are available on CodePlex
http://msftdbprodsamples.codeplex.com/
http://www.codeplex.com/Release/ProjectReleases.aspx?ProjectName=MSFTDBProdSamples&ReleaseId=4004">
http://msftdbprodsamples.codeplex.com/
http://www.codeplex.com/Release/ProjectReleases.aspx?ProjectName=MSFTDBProdSamples&ReleaseId=4004