I have seen a lot of people asking about when they can upgrade from MCPD on Visual Studio 2005 to MCPD on Visual Studio 2008.
Short answer: In about 6 months.
Longer answer: (quoting Gerry) The upgrade exams are a composite exam that pulls from the requisite MCTS and MCPD exams. As a result, they rely on the completion of those exams first. Our MCPD exams for 3.5 won’t be live until the end of  and beginning of . So upgrade exams won't be available until early 2009. Sounds like the prep guides for PD and upgrade exams will be posted in the next month or two. In the meantime, you can read about what's being planned here.