Before I completely understood which exams I have to take to upgrade MCPD certifications, I thought that 70-551 (MCPD Web), 70- 552 (MCPD Windows), 70-553 + 70-554 (MCPD Enterprise) were all necessary to take.

I draw a diagram which shows which exams are included in upgrade exam. As you can see upgrade exams are actually pack of existing .NET 2.0 exams. Personal "certification planner" on MCP site shows all possible exams you may take for your goal, but sometimes it is not the shortest.

If you aim to have MCPD Web, MCPD Windows and MCPD Enterprise certifications you have two options;

• with 3 exams : 70-551 + 70-552 + 70-554. This is most cost effective but since 70-551 and 70-552 both contains 70-536, you will take 70-536 exam twice.
• with 4 exams : 70-553 + 70-554 + 70-547 + 70-548. You will pay for one more exam but this will cover all exams but you will not take 70-536 twice.

For upgrade exams Self-Paced training kits can be used, they are combination of .NET 2.0 exams but lets you achieve your certification goal with taking less exam, so you pay less. If you are new to .NET or do not have MCAD/MCSD.Net certifications all exams have to be taken separately.

Hope helps...

Yesterday I took exam 70-554, which is second part to upgrading existing MCSD.Net certification to MCPD Enterprise developer. Exam 70-554 is combination of 70-529 TS and 70-549 PRO exams.

I had to take this exam twice since first time I almost passed (I guess I missed with 2 questions). 70-529 had many WSE 3.0 questions which I was not so strong.

I did well with 70-549 exam for both first second time although I did not study for this exam (.NET experience since 1.0 beta 2 helped). For the second shot studying WSE 3.0 worked for the exam. 

WSE 3.0 Quickstart samples, hands on labs and videos from WSE 3.0 downloads and self-paced training book for 70-529 are good resources for WSE 3.0