1_
Firstly you should install NASM
http://sourceforge.net/projects/nasm/files/Win32%20binaries/2.05.01/nasm-2.05.01-win32.zip/download
and Copy to your bin directory at msys.
2_ download Git
http://code.google.com/p/msysgit/downloads/list
I just downloaded
Git-1.6.5.1-preview20091022.exe version.
and entering command like that
"git clone git://git.videolan.org/x264.git c:\x264"
3_download yasm
http://www.tortall.net/projects/yasm/wiki/Download
and copy to bin directory in msys.
make sure rename to yasm.exe.
4_ making
:: Static to MinGW folder:
./configure --prefix=/mingw
make
make install
or
::static build
git clone git://git.videolan.org/x264.git /c/x264
cd /c/x264
./configure --prefix=/static
make
make install
If you learn to command MAKE more .
http://ask.nate.com/qna/view.html?n=159212