I'm travelling to the UK in a week, and have an 8700 with Cingular here. I want to get a sim card so i can use it mostly for UK to UK calling. Anyone have any recs on what/how/where I should get, and what network is best. I'll mostly be in London, so i assume they will all be good.

First question: Is your 8700 unlocked? If not, your 8700 will not be usable with another provider's SIM card.

If it is unlocked, my recommendation is Vodafone.