Hey great news! If youre an MSDN subscriber you can download Windows Vista Beta 1 today otherwise TechNet subscribers need to wait till next month's release. Check this website!
Some people are a little confused by it and think that its just Windows XP by another name because of the GUI screenshots. Remember beta 1 of WinXP? It looked just like Win2k. Then beta 2 released and Luna got added and it looked a lot better. Think along those lines for beta 2 where all the cool "user experience" stuff gets put in then.
So Windows Vista beta 1 is a "testing" release. Its for IT Pros and Developers to test their apps on and ensure that they work properly. Its to try out Avalon (new presentation subsystem that drives AeroGlass), Indigo (communications subsystem) and WinFX (the evolution past Win32). Its to test the security changes such as IE7 and impacts of implementing Limited User Access (LUA) (and now called User Account Protection (UAP)). Might talk a bit more about what those mean to the IT Pro in later blog posts.
BTW. AeroGlass is actually enabled in the beta 1 build but you need a video card powerful enough to drive it. I use an ATI Radeon 9550 256MB RAM and it runs really well. Lovely transparency and screen effects. Now when I compare even at this early stage, the GUI of WinXP and Vista, the Vista one with AeroGlass already just looks cool.