The Perseid meteor shower is the most famous of all the meteor showers, and has been visible since the end of July, with one meteor an hour crossing the sky. But the action begins to hot up by the 10th August, with up to 15 mwteors an hour being visible if the sky is clear.
The peak dates to see the Perseid meteor shower are between the 12-13 August when up to 100 meteors an hour can be seen! There will also be good rates either side of the peak shower between 11-12 August and 13-14 August.
Check out the Met Office site to see a map forecasting when it is visible in your area. You can also download an excellent PDF about watching the Perseid Shower.
There is also a good short video explaining the Perseid shower on the BBC weather site: