We are on Creo Elements/Pro 5.0 and we are using MSVC 2008. PTC supports the compiler, linker, libraries and header files that were shipped with MSVC 2008. However; that doesn't mean that you have to have MSVC 2008. You CAN build Creo Elements/Pro 5.0 compatible programs using the Express version of the IDE and the correct Windows SDK. If you don't want to go that route then I would suggest getting a full copy of MSVC 2008.
I would not expect the 2010 version to be compatible with Creo Elements/Pro 5.0 because PTC compiles their libraries with 2008. Between 2008 and 2010 Microsoft has changed the core C/C++ runtime libraries which would not be backwards compatible with the PTC libraries that were built with 2008.
Patrick Williams | Engineering Systems | o: 616.698.3766 | c: 616.947.2110