Skype didn't hear back from Apple soon enough about receiving approval of their WiFi based iPhone app is my guess so they went with what some would consider a bigger gun. Nokia.
Today at Mobile World Congress Skype announced that the next pre-load of Skype will be with Nokia on the Q3 release of the Nokia N97, a very hot device that Nokia first unveiled last December at Nokia World.
One of the things that was obvious is that Skype has learned a lot from their SkypePhone partner, iSkoot, and the iSkoot created client that comes pre-installed and th server that sits inside the carrier network. That intellectual capital was espoused by Josh Silverman who rattled off all kinds of stats related to the 3 customer, many of whom are Skype users, who chose to switch.
Basically the underlying message the Skype CEO shared was carriers who will work with Skype will pick up users who spend more money than the non-Skype using mobile phone customer, or at least they did with 3.
One more note. With services like Skype coming out on the new Nokias, and an already existing Skype-Boingo relationship, and an existing Boingo client already running on the N and E series phones, one doesn't have to start seeing the alignment that is going on, and its all very smart and well thought through on all of the companies parts.