IbanezFreak777 - thanks, I'll check them out.
MarkE - I'll be traveling with two women, so I should get by just fine bartering.
Jono - Coming the last week of November (over the US Thanksgiving). Staying in London - Trafalgar Square.
Also, from reading a bit more, seems that using my debit card and getting cash as needed in London is a good way to go. Turns out my bank is really nice about fees... I only pay the ATM fee in London and if I use my card as a VISA for purchases, I pay the 1% fee that VISA imposes.