The skinny:

• Where? https://downloads.channel8.msdn.com
• What? Loads of dev and design products
  • Visual Studio 2008 Pro
  • Expression Studio
  • XNA 2.0 and XNA Creators Club membership
  • Windows Server 2003
  • SQL
  • Express Editions
  • Virtual PC
• Who? Available to 2 MILLION higher education students in the UK. Another 5 MILLION further education students throughout the year
• Why? See Bill talk about it here
• When? Now

Read more about it on Ed Dunhill's blog with some great links - DreamSpark - Free Software for all UK Student

Read more about it here Microsoft Giving Away Free Developer Software To Students