SourceForge and its spiritual descendants such as CodePlex and github are wonderful places for free and open-source software to live, but finding programs based on what features you need is next to impossible. It's one of those really difficult search problems for which we are unprepared. The best answer is not to search the source repositories yourself, but look for a good curator. Someone who has tried all the software, compiled articles on what each one can and can't do, and has recommendations for the most common use scenarios. Failing one expert, however, you could always go for the wisdom of the crowd and ask on a forum. There, if everyone who answers has tried two different programs, there will be enough overlap that you should be able to pick the best one that does what you need.
So, basically, there are websites that allow people to host software projects, but you need the wisdom of crowds to navigate them if you're looking for the perfect tool for a particular task rather than a specific tool by name. But then you need to find and elicit a response from the right crowd to make your decision, which is another problem.
Mokalus of Borg
PS - And if your responding crowd is too small, you need to trust them.
PPS - And trust is a problem.