If you go to sourceforge.net and plug in the word "bicycle" around 45 hits come back, of which at least three or four are dedicated spoke calculators or programs that clearly include that functionality. I would go find the links myself but I am in the middle of something else right now, and also I bet the search might be better pursued in that more general way because the chances are high you may see something else you like too.

Some of the programs there are works in progress.. but they usually work on some level.If you spend a few minutes poking around you'll quickly learn what clues you can use to make intelligent decisions about which programs are likely o work more than others. (Programs that are updated frequently or which have more than one or two developers usually work, some are amazingly high quality and the variety of functionality on sourceforge represented is quite amazing.)