since no one gave a satisfactory answer to my question, I am posting my final decision here.
I could not find a way to create flex in vs 2005 or vs 2008. Instead, I use flex, which is distributed with cygwin, which is quite recent. in order to save on the complexity of installing cygwin on every machine on which I need to use flex, I just saved the dependencies: cygwin1.dll and cygintl-8.dll.
There is only one caveat - cygwin flex also depends on m4, although you will not see it on the go dependencies. he must be in the way, which makes him pain. you can use cygwin m4.exe, but it also depends on cygwin1.dll, which must be in the path to run m4.
However, I just check all these files on my svn in the tools folder, and then whenever I need to develop on another machine, get my code and compress svn, copy m4.exe and cygwin1.dll to the \ system32 windows and I'm in business.