S900 Smartphone Windows Mobile 6.1 WIFI Quad Band Bluetooth FM Touch Cell Phone

My sister recently moved to Belgium. She has access to WiFi at home, so I'd like to send her a mobile phone that can run a Skype client. Requirements are WiFi, can work on Belgian / European carriers, runs Skype, and has excellent battery life. Anyone have any suggestions?

I have HTC P3450 device which has Windows Mobile 6.0 Professional.
Can I install or upgrade(?) it to Windows Mobile 5.0 Pocket PC Phone Edition.

And I also want to ask that if windows mobile 5.0 device is upgraded to windows mobile 6 . Is it possible to go back to windows mobile 5.0?

Please help me in this.

Thanks

What is the technical difference between a SmartPhone and a PDA?
What is the technical difference between a SmartPhone and a PDA?Is prescence of an OS in the phone an difference?
How to recognize a phone as an PDA or SmartPhone given a description of its features?

Is there a smartphone that will connect to the internet without a data subscription?
Looking to buy a smartphone or blackberry that i can check my email or browse the internet using just WIFI, without paying for a voice/data plan from Verizon. Is there a phone that will do this ?

I'm going to be graduating from college next semester and will finally be forced to leave my parents cell phone plan. Everyone in my field of study (Public Relations) has a blackberry or something similar and I'm ready to join the club.

The phone I have now is an archaic Motorola flip phone with Verizon and I don’t want to overwhelm myself with a phone I can’t figure out.

So my question is what would be the best smartphone for a first time buyer?