Getting around in London I

Still the quickest way to travel long distances in London is the Tube or the red London busses ... In order to get you going as quick as possible it is advisable to purchase a visitor Oyster Card before your journey; for example via the Visit Britain homepage (http://www.visitbritainshop.com/deutschland/mobil-in-gb/product/visitor-oyster-card.html?utm_source=google&utm_medium=ppc&utm_term=oyster%20card%20london&utm_matchtype=e&utm_campaign=DE_London_Transport&utm_country=germany)
    But what is an Oyster Card actually? Well, Oyster is a plastic smartcard you can use instead of paper tickets. You can put Travelcards, Bus & Tram season tickets and pay as you go credit on it.

Oyster is the cheapest way to pay for single journeys on bus, Tube, tram, DLR, London Overground and most National Rail services in London.
You can:

• Store credit to pay as you go
• Set up Auto-top up so you never run out of credit
• Add Travelcards if they're for longer than a day
• Add Bus & Tram Passes
• Add Bus & Tram and New Deal discounts
• Add National Railcards or Gold Card discounts
• Get student and child discounts with an Oyster photocard
• Protect your card from loss or theft 

(These pieces of information are taken from the TfL homepage: http://www.tfl.gov.uk/tickets/14836.aspx)

In 2006 I had used my Oyster Card daily and to my surprise it still worked in 2011 although I hadn't been using the card once after December 2006. However nowadays you cannot top-up your card with cash at the Tube stations anymore as most of the counters are closed. They were mostly replaced by top-up machines that accept credit cards only. Nevertheless, in most cornershops - as I found out - you can still top-up your Oyster Card with cash.