As part of the Microsoft Windows Server 2008 Certification program, the Microsoft Partner Program is offering $150 credit to the first 5000 partners who sign up. You can find out more here: https://microsoft.mrmpslc.com/InnovateOnWindowsServer/KeywordAdvertising.aspx.
Note that it requires $5 to sign up.
Supposedly you can also receive $75 credit for signing up for the Microsoft Referral Program and $100 for each customer you sign up. I'll talk more about this in a follow up blog.