I think there are now dual SIM adapters for the Lumia series, although the ones I have seen are external and you cannot have both SIMs `live' at the same time - flipping between the two is as easy as switching to `flight mode' and back again though.
+Steve
[size=2]Steve Gold
PO Box 1014, Sheffield S10 5YG, UK
Home mobie: Telefonica O2
Other UK mobiles: 3, Vodafone, Virgin
Foreign SIMs: Toggle (multi); Germany (Fonic); Poland (Orange PL);
Skype: stevewgold