Specifically for VS to CMake/GYP

Specifically for VS to CMake/GYP:

vcproj2cmake
vcxproj2cmake (not a
typo!)
gypify.py is a .sln/solution-reading Gyp file
generator. Gyp is a Cmake alternative, currently being used by the Chromium project (base for Google's Chrome browser). Gyp will output Makefile, Visual Studio or XCode build files (see Gyp's '-f [make|scons|msvc|xcode]' switch). This Python script is quite
promising, I'm hoping to modify it soon to correctly specify header-containing folders for gcc's '-I' include parameter.

Other Cmake/Make-related conversion tools:

Make It So Converts Visual
Studio solutions to Linux gcc makefiles
sln2mak C#
project
sln2mak Perl
script
GUCEF Project includes
the ProjectGenerator tool, for Cmake
gencmake (ruby)
– KDE Project
'pbtomake'
says it can convert XCode xcodeproj/pbproj files to Makefiles (maybe outdated)

Cheers

Rich