1) Use VS2003. VS2003 installs on 64-bit Windows and will generate code that always runs on the 32-bit CLR.
2) When using VS2005 you can select that you want the assembly you're generating to be 32-bit only (the default is "ANY CPU", which will float to the 64-bit CLR if one is available).
3) Use the 32-bit C++ compilers (C++ has different compilers for targeting each platform). The 32-bit compiler runs on 64-bit Windows and will generate code that runs as 32-bit unless the user specifies /clr:safe.
Hope that helps,
Kang Su Gatlin
Visual C++ Program Manager