Skype is for the iphone now.

You can go either way unlocked by the factory or jailbroken. Be aware though, any time an update is issued for the phone it will break the jailbrake unlock. If you want to buy a phone that is unlocked, its not cheap. I think the going price for a factory unlocked 16gb 3g is around $650 and unlocked for can only be purchased in a few countries.