There have been rumors of Skype integrating into Windows Phone in future. And many information are pointing that the integration will not take place this year. However, during MIX11, Microsoft showed off a Skype app that is slated for late Fall 2011 release.
In my opinion, this is much better than waiting for the integration which we have no idea when. It has been really frustrating to see other OSes “progressing” while Windows Phone is playing “catch-up”
With Windows Phone upgraded to Mango (Windows Phone 7.5), it actually has a long way to go to convince people to use it and to convince existing users that they have not waited in vain.