Oi! All you Brits out there! (London specific)

[celtic_tigress]

Hello ladies, members of the all-knowing flist! I have a few questions! I have a very good friend who is likely moving to London this fall for a semester of uni, and she'd like some advice on various things from whomever lives/has lived in that venerable city. She'll be going to University College London, and right now is considering housing. How is the public transportation in London generally? Should living very near campus be a priority for her? What other advice can you give her on living there? She's lived near a large city most of her life, but hasn't lived in anything more urban than the suburbs.

Any and all words of wisdom will be welcome! Even if you don't have direct knowledge of the city, either as a resident or visitor, please send anyone you know who does towards this post, thanks!