What steps do i need to take to vivsit the UK from USA?

You need a passport and it HAS to be a passport book, not a card. You don't need a visa for only a week (US passport holders can go to the UK for up to 6 months without one). There is accommodation of all kinds and the best thing is just to research online and see what you can find.

Public transport in London is excellent and everything you need to know about it is at http://www.tfl.gov.uk/ For a look around all the main things to see, look at http://www.theoriginaltour.com/

If you haven't done an international flight before, the big differences are at the other end. Flying inside the USA, all you need to do when you arrive is get your checked baggage from baggage reclaim. Going to another country, you go through immigration/passport control first where they will quiz you about your visit. Then you reclaim your bags and then go through customs. The UK operates a colour-coded three-channel system and if you don't have anything with you that you shouldn't have, walk through the green one.

Take a pen and a note of the address where you are staying on the flight. The flight attendants will come around with UK landing cards and you will need those to fill the card in. You hand the card over with your passport at immigration. Going back, you will need the pen again to fill in the US customs form.

Think about how to bring money. Cash, traveler's checks (which you can change into cash at any bank), or rely on whatever kind of plastic card you have? Of course the UK doesn't use dollars so you will have to get used to pounds and pence instead of dollars and cents.

Get a good guidebook - it is the best help you can get.

Your passport a return ticket, enough money to live while you are here, if you are American you do not require a visa and some research around accommodation, London is set up for tourists, so very easy to book tours, or jump on a water taxi/bus to see the sites

http://www.visitlondon.com/

Well getting passport and other are basic things you need. Than fixed a specific destination where you will stay. Than book a living place or hotel online using online as arunparking.co.uk. Apart from that you should estimate the location where you want to live and then fix your hotel and parking place for your car if you have, because by online booking you can get a lot of extra benefits.

Passport/ Photo ID/ Return Plane ticket- if staying more than a couple weeks they may ask about Money

Just came back from London Monday- had a great time

Get a guide book and figure out what you actually want to see and do.

Work out a budget so you know how much you have to spent; then get a plan that fits it (no point wanting to stay at the Ritz if your budget better suits a Travelodge)

You need passport approval & such other things

Do it all online..Cheaper & fun....