Don't panic!  Travelling around London is really quite easy when you
know how.  (The days when I knew all 328 Underground stations off by
heart are long gone, but here's an easier way.)

For information about the Underground system, go to tfl.gov.uk/tube
There are travel cards and "Oyster" cards for repeated journeys which
can save you money, especially if travelling after 09.30.

If you are travelling further out, beyond the Underground area,
details of all stations and fares can be found at nationalrail.co.uk
Suburban trains tend to run at half-hour intervals or less.  Again,
travelling off-peak is cheaper and more comfortable.

Have fun, as I did on the Chicago EL!
Paul Collenette