OK, just arranged an incoming transatlantic call from an apple phone, my N900 rang and I could answer.
Also made a sucessful outgoing transatlantic call to same apple phone, but it still seems wonky.
It seems that contacts drift on and offline on my N900 and my N900 status does the same on my desktop client without explanation.
Anyways it is working for me, though I somehow still can't make a call or see an online status between my Ubuntu Skype 5.3.0.1 Linux Beta over my home laptop which works for showing online and calling transatlantic to an apple phone, but somehow doesn't show my N900 online via either home wifi and my 3.5G service.