There is a third, Truphone. Like Nimbuzz, it doesn't feature a keypad and will only allow calls to existing Skype friends, ie no Skype Out, which is a bit of a pain. They do imply this is only a limitation of the current version, but I'm not holding my breath for the capability to be added. If you think about what it would mean, it would be the same as T-Mobile allowing all its customers to make calls on Vodaphone. Hardly a means of ensuring a good/any income.