Are you sure you can't just run cl.exe without any input for it to report its version?
I've just tested running cl.exe in the command prompt for VS 2008, 2005, and .NET 2003 and they all reported its version.
For 2008:
d:Program FilesMicrosoft Visual Studio 9.0VC>cl
Microsoft (R) 32-bit C/C++ Optimizing Compiler Version 15.00.30729.01 for 80x86
For 2005, SP 1 (added Safe Standard C++ classes):
C:Program FilesMicrosoft Visual Studio 8VC>cl
Microsoft (R) 32-bit C/C++ Optimizing Compiler Version 14.00.50727.762 for 80x86
For 2005:
C:Program FilesMicrosoft Visual Studio 8VC>cl
Microsoft (R) 32-bit C/C++ Optimizing Compiler Version 14.00.50727.42 for 80x86
For .NET 2003:
Microsoft (R) 32-bit C/C++ Optimizing Compiler Version 13.10.6030 for 80x86
EDIT
For 2010, it will be along the line of:
Microsoft (R) 32-bit C/C++ Optimizing Compiler Version 16.XX.YYYYY.ZZ for 80x86
or depending on targeted platform
Microsoft (R) C/C++ Optimizing Compiler Version 16.XX.YYYYY.ZZ for x64
For 2012:
Microsoft (R) C/C++ Optimizing Compiler Version 17.XX.YYYYY.ZZ for $$$
where $$$ is the targeted platform (e.g. x86, x64, ARM), and XX, YYYYY, and ZZ are minor version numbers.
For 2013:
Microsoft (R) C/C++ Optimizing Compiler Version 18.XX.YYYYY.ZZ for $$$
where $$$ is the targeted platform (e.g. x86, x64, ARM), and XX, YYYYY, and ZZ are minor version numbers.
For 2015:
Microsoft (R) C/C++ Optimizing Compiler Version 19.XX.YYYYY for $$$
where $$$ is the targeted platform (e.g. x86, x64, ARM), and XX and YYYYY are minor version numbers.