I hate to say it, but being a US citizen really won't help you (it won't hinder you either) when it comes to UK immigration. The countries may be allies, but it doesn't make immigration any easier from the US to the UK, or the other way around.
Expat Forum For People Moving Overseas And Living Abroad
A forum community dedicated to expatriates and enthusiasts. Come join the discussion about residency, taxes, documents, visas, travel, health care, finances, banking, classifieds, and more!