At Skype’s Users Forum we do receive many requests for Joost Invitations.
Although it is understandable that people link Joost with Skype (they have the co-founders Niklas Zennström and Janus Friis in common), Joost is not related to Skype.
OK, some Skype Beta Testers are also Joost Beta Testers but this has more to do with their love for testing Peer to Peer software.
So, no Joost Beta section in Skype’s Users Forum. However, there is a very good site called JoostFan with an excellent JoostFan Forum.
You can also find the links in the right hand menu of this blog under “Joost related links”