Here is what our own sysadmin was able to do from clues provided by jeremy.m in comment 8 to get it working on our RHEL5 w/python 2.7.2. I hope it helps someone else...
"When you download the package, it's a compressed tar ball. When you expand it, it goes into a folder (pymssql-2.0.0b1-dev-20111019) with a bunch of sub-folders. One of those sub-folders was "freetds". All I did was a "rm -rf freetds" and then a "python setup.py build" and a "python setup.py install" and I was done. (Of course I could have done this all with just the one "install" command but I'm a little careful of things.)"