After some initial futzing with some partial solutions I found posted online, I was eventually led to a Microsoft site. To my shock and amazement, I found the answer I needed at msdn.microsoft.com. A search on "enumprocesses" revealed all the code I would need to write a decent api (for NT 5 anyway - not sure if it works on NT 4).
The code listed, however, relies on a library that comes standard with the MS SDK (psapi.lib - note the "ps"), but isn't usually installed on a system by default. So, I need to triple check that it's ok to distribute with a tarball. What I've read online indicates that it's perfectly acceptable to distribute this lib (heck, I downloaded it off someone's site), but I want to make sure before I'm sued off the planet or something.
I suppose I should also add cygwin support at some point as well.