Microsoft has released the latest build 5231 to testers on the Microsoft connect website. They have posted: CD images, DVD images, Checked Builds for Developers, and the SDK. Downloads range frm 1.5 GB for the x86 to over 2.8 GB for the x64 versions.

Update: "Dear Windows Beta Tester, The Windows Beta Team announces the availability of Windows Vista, Build 5231, on Microsoft Connect. This interim builds offers a view of alterations to Vista incorporating feedback gained during the testing of Beta 1 and Build 5219. This build is not beta quality but is offered as a preview or our progress towards Beta 2. This build has many references to Beta 2 in the user interface. Those references exist as we build towards the beta 2 release. 5231 is NOT Beta 2. You can download this release now from Microsoft Connect. Important notes: Windows Vista, Build 5231 is compatible with Product Keys labeled as "Vista 5219 and up product keys." If you have not yet obtained the appropriate Product Key, you can do so now via the Product Key link on the Download page of Microsoft Connect. You will be required to activate Build 5231 within 14 days of installation. Please note: This release is for Vista only. No server build will be made available. We recommend a clean install for this release. Upgrades from Beta 1 or Build 5219 are not recommended. If you choose to install 5231 you will not be able to upgrade beyond this build. We look forward to your feedback on this new build! The Windows Beta Team"