To access street view go to Google Maps and search for an area or drop using the Maps app on your iPhone drop a pin and then click the little orange man (see also How to view Street View on an iPhone). There is a little orange man that will appear on the left side if street view is available for that area, if not he will remain greyed out. At present it only covers a handful of areas (mostly the major cities) but these will be added to quite quickly over the coming months I’m sure. If you go to the overall view of the UK and drag the orange man it highlights areas that are live, the same is true at a more zoomed in street level, dragging the orange man shows which streets are covered in blue.

Here’s how it looks on the iPhone:

Google Street View cars have been spotted in numerous other areas that are not yet live, these will getting processed for face blurring, etc and get added eventually. It looks like Google has made a good effort at blurring out car registration plates and faces but a few will always slip through the net: