Are you interested in testing Mac software? You can do so at MacDeveloper.net. I met this site when reporting issues with Trailrunner and the TR autor pointed me to this site, where he has just opened an account.
Meanwhile MD is getting traction and new projects are popping up every week.
And - your time is honored: when you find an issue that is accepted by the developer, you will get points for this. If you have enough points, you will get a rebate on the license or even a license for free -- this depends on the developers and each individual project.