Skype has ordered Nimbuzz to remove support for Skype in their application by October 31st - Halloween no less, but this is no trick. Nimbuzz currently has 30 million users and the theory is that Skype is removing support for third-party access to their service ahead of their planned IPO. You probably recall the fring vs. Skype battle where fring also lost access to Skype services back in July.
However, a Skype spokeperson denied the IPO was the cause:
Skype has just jumped the shark. They are no longer the cool kid on the block. The more they try and put up a walled garden, the more chance competitors will take market share. "Mr. Bates (Skype's new CEO), tear down this wall!"