SQL Server 2008 July CTP is now available at https://connect.microsoft.com/SQLServer/content/content.aspx?ContentID=5395. The samples for the July CTP are available at http://codeplex.com/SqlServerSamples along with your favorite SQL Server 2005 SP2 samples.
Some folks have been confused about how to download the samples either from the portal page or from various projects. You just click on the Releases tab and you'll find MSIs which are the best way to download the sample code and sample databases. On the portal project (http://codeplex.com/SqlServerSamples) the MSIs contain all the sample code for all technologies. If you go to a particular project page listed on the home wiki page of the portal project, the Releases tab will contain installers for that particular technology. For example, the Releases tab on the Analysis Services product sample project will have MSIs which just contain Analysis Services samples. The same goes for all the rest of the other technology areas. The AdventureWorks sample database project (http://www.codeplex.com/MSFTDBProdSamples) also has a Releases tab, and the MSIs there can be used to dowload the various kinds of sample databases. There are always separate installers for each hardware architecture (x86, x64, IA64). Select the installer which matches the type of hardware you are using. For the database samples there are different kinds of sample databases to choose from (OLTP, OLAP/DW, Light (LT), Scripts). One thing that's different about the SQL Server 2008 database installers is that they attach the database for you (except the scripts installers which are for building the database yourself if you want). For more information about how to use CodePlex take a look at http://www.codeplex.com/SqlServerSamples/Wiki/View.aspx?title=HowToUseCodePlex&referringTitle=Home. Thanks!