Tips and advice for moving to London?

Well, I finally have my UK passport and I'm gearing up to move to England in May/June when this semester is done. I'm only planning on spending 3-4 months there, but seeing as how I've never been there before, I was wondering if any of you have any tips from your moves to the UK.
I'm hoping on moving to London, but my heart's not 100% set on that. I'm an architect, so I was thinking my chances of getting a job would be best there. I imagine that when I get there I will have no confirmed job nor a place to live.
What areas of London are the best to live in? (Economy being my #1 priority as I need to save $ for tuition next year) What's the best way to look for a place there? I assume I'll be sharing a flat with a few people.
Basically, any advice you can throw my way would be great. I assume many people have come to this site asking the very same questions I am now, so if there's an existing thread you can point me to, that would be great too.
Thanks!