Comment Free WiFi (Score 1) 1095
In general you have to pay for WiFi in chain cafes (Starbucks and the like). However, many of the independents and smaller chains offer it for free.
There's free WiFi and power points in the cafe at the British Library.
The cafe in Foyles bookstore (a geek venue in its own right) on Charing Cross Road is pretty geek friendly. It's handy for the computer section, there's often free live Jazz playing, and (when it works which is not always) there's free WiFi. Oh and the cake is good there.
Tottenham Court Road is the local centre for technology shopping in the area if you find you've forgotten to bring something vital.
The National Film Theatre under the south arches of Waterloo Bridge has the broadest arts cinema coverage in the capital. The Electric Cinema in Notting Hill Gate is the comfiest cinema in the capital.
For non-geeky but interesting things to do while you're here pick up a copy of Time Out. I'd recommend the 100 club on Oxford Street on Monday nights though.