Im starting to test out the framework for my new home automation software this weekend and got Python-serial library working. I was able to retrieve the registers from the UPB PIM interface in a proof-of-concept program.
I was toying around with using Mono (Opensourced .NET implementation) and tried a pilot program with that as well. Sadly, the state of Mono's serial library is still broken from the years ago I first tried it. The lack of seeming interest in testing that System.IO library is echoed in my interest in pursuit of this option.
Python-Serial Docs - http://pyserial.wiki.sourceforge.net/pySerial
Pytomation project page: http://pytomation.wiki.sourceforge.net/