Yep. This short video (under 2 minutes) from TfL provides a good explanation on how to use it - it's very straightforward...

There's more information on the TfL website here:
tfl.gov.uk/contactless

There's also information on acceptance of cards issued outside the UK - note that all Amex cards, regardless of where they are issued, can be used.

Note that all the travel for one day will be collated and billed to your card in a single transaction the next day, so if your card has foreign transaction fees you won't pay them on the fare for each individual journey, but rather for all the days journeys combined together.

Lastly, contactless (and Oyster) can be used for pretty much any public transport journey in London - notable exceptions are the Heathrow Express, Heathrow Connect (for journeys to or from Heathrow itself), and trains to Luton, Stansted and Southend airports (all airports with a London prefix). As of January 2016 contactless and Oyster can be used on all trains between London and Gatwick airport.

This map shows the boundary of the 'pay as you go' area, within which contactless and Oyster can be used.