Hi Robert,
All my Xcode specifications (pbcompspec) are in:
/Library/Application Support/Developer/Shared/Xcode/Specifications/
The compiler is in:
/Developer/Cocotron/1.0/Windows/i386/gcc-4.3.1
/Developer/Cocotron/1.0/Windows/i386/g++-4.3.1
Which are pointed to by the specifications.
In the projects, the SDK is set to Current Mac OS, and the compiler is set to the Cocotron Windows compiler.
If you have existing binaries use those, if you want to do it from scratch again, Pauli has a nice writeup here:
Apologies for this getting so complicated, the tools need a little TLC right now.
Chris