The June issue of Linux Journal magazine has included a brief writeup on OpenSTV in its New Products section. You need a subscription to view the magazine online, but here is the text of the article:

OpenSTV

Ever feel like voting your conscience by supporting the Penguin Party rather than settling for the lesser of two "Republicrat" or "Demopublican" evils? To solve this dilemma, alternative (and Constitutional and increasingly popular) voting methods, such as single transferable vote (STV) and instant runoff voting have evolved that allow one to rank candidates in an election. If your Penguin Party candidate has no chance in hell to win, your vote counts instead for your lower-ranked choice who has a shot at winning. Sorting out these voting preferences is the job of OpenSTV, now in version 1.1, an open-source application that tabulates votes according to the respective voting rules. Data generally comes from paper ballots and is dumped into OpenSTV. The lead developer says that some of the voting rules have been extensively verified by comparing the results over hundreds of elections against other software". OpenSTV runs on Linux, Mac OS X or Windows and can be downloaded from SourceForge.