The Visual Studio .NET 2005 Community Technology Preview can't be normally installed on any version of Longhorn (the VS installer don't permit it).
Miguel Jimenez on his blog has posted a patch utility he has built that exactly do this: you can install the Visual Studio 2005 on any Longhorn build.
Interesting... 
The Microsoft File Checksum Integrity Verifier tool is an unsupported command line utility that computes MD5 or SHA1 cryptographic hashes for files.
This is an interesting utility, but I don't know why Microsoft has decided to not provide support for this utility. Microsoft Technical Support is unable to answer questions about the File Checksum Integrity Verifier... not good! 