Java, C, C++ and perl source code implementing election methods including Borda, Condorcet, Raw Rated, Approval and Instant Runoff voting.
I've moved hosting to code.google.com, go here:
Voting Software on Google Code
|Virtual Round Robin (Condorcet)||Java||C||C++||perl|
|Instant Runoff Normalized Ratings (IRNR)||Java||C||C++||perl|
|Instant Runoff Voting (IRV)||Java||C||C++||perl|
|Raw Rating Summation||Java||C||C++|
|Single Transferrable Vote (STV)||Java||C|
|Histogram (for data display)||Java||C||C++||perl|
The Java library is currently most tested because I have been using it to develop the Servlet based Election Calculator and BetterPolls.com.
Each implementation includes a command line utility for processing url query formatted vote data.
All sources copyright Brian Olson. Free for non-commercial use. Licence for other use negotiable.
See also this comprehensive python single transferrable vote (STV) implementation.