London is, above all, a walker's city, and will repay every moment you spend exploring on foot. Of course, that may be of diminished appeal when you've got 30 minutes to scramble to the other side of town. Here are other options:
By far the easiest and most practical way to get around is on the Underground, or "Tube." Trains run daily from early morning to night. Buy an Oyster card for £3, which will allow you to use London's transport at a lower cost than using paper tickets. The plastic card can be topped up as often as you want, and your £3 will be reimbursed when you hand the card back. Alternatively, buy a Travelcard pass (from £4.80 per day), which offers unlimited use of the Tube, buses, and the commuter rail. Avoid rush-hour hell—the rest of the day this is a pleasant and quick way to move. Note: The Tube is undergoing a major overhaul. Keep an eye out for information on line closures and alternative routes. Checkwww.tfl.gov.uk for details.
The commuter rail system is an over-ground network that connects outlying districts and suburbs to the center. Prices are comparable to those of the Underground, and you can easily transfer between the Underground and other connecting rail lines at many Tube stations.
Buses crisscross all over, and are a great way to see the city. Their routes are more complicated than the Tube's, but by reading the route posted on the main bus stop and looking for the number and destination on the front of the bus, you won't go far wrong. Service is frequent.