On an agile project I'd been using Skype to track defect conversations I was having with developers. We had no easy way to track bugs, and the need to get things fixed ASAP removed the benefit of formally tracking bugs. The biggest problem with using Skype was the distributed and fractured information.
Solution: Google Wave! Create a wave with all your developers and testers and call it after the name of your sprint. List defects one by one, give them an id and description. Use colour coding to indicate the state of the defect. Developers and testers can comment on each individual part of the wave/defect. Completely simple! All the information is contained within one location and is accessible to all. Next level communication!