Back in June, Microsoft increased the volume of free credits for most MSDN subscribers. It has now added Azure credit to two other MSDN programs: MSDN Platforms and Visual Studio Test Professional with MSDN.
Platforms subscribers score $US100 in credit each month, while Test Professional subscribers receive $US50 in credit per month. Hit the announcement post for more details.
Expanding Windows Azure MSDN Benefit [Brian Harry's Blog]