Windows Vista SP1 x86 (FULL) is now on the TechNet Subscriber download center. It's the 32bit fully integrated version of the OS. I just downloaded it, burned a DVD and have the install running in a Virtual PC 2007 virtual machine. Finally!!!
My download took minutes. Being first helps. It flew down the fiber pipe to my house at 1.8meg per second. I wish all my downloads were that fast. Your mileage will vary. I'm planning on "enhancing" my VM first thing. I'm going to enable IIS7, then drop PHP, MySQL and WordPress on it. When I get it working, I am going to do a screencast on the process. Getting ready to record how to do that with Windows Server 2008 in a few minutes. Enjoy!
[UPDATE for 2/25/2007] I compared the size of the .ISO I downloaded from the TechNet subscriber download area to the one I pulled directly from the internal build server. Exact match on number of bytes. Golden goodness. I am also very happy with it's performance in the VM. I'm told most of the speed is coming from Intel VT. Rock and roll baby.
To be clear, my host environment is a Lenovo ThinkPad T61p running Windows Vista Ultimate SP1 x64. I'm running the x64 version of Virtual PC 2007 although very little of VPC 2007 is actually x64. I am using the VM additions from Virtual Server 2005 R2 SP1 (13.813). The VM is of course the x86 version of Windows Vista Ultimate SP1.
[UPDATE for 2/28/2007] The x64 DVD .iso is now online. See http://blogs.technet.com/keithcombs/archive/2008/02/28/i-spy-the-windows-vista-sp1-x64-full-dvd-integrated.aspx for more details.