1. go on walking tours so you can see all the side streets and stuff. http://www.walks.com/
2. there's a huge geek community, check out http://www.geekery.in/london/ http://upcoming.yahoo.com/place/.2P4je.dBZgMyQ--
3. museums are free, check out the imperial war museum, V&A, british museum
4. starbucks has a deal where you can get wifi with the purchase of a starbucks gift card, pub often have wifi access too
5. use http://www.famouslocations.com/ to find spots from different films (just realized the filmed part of eyes wide shut 6.outside my place... creepy)
6. eat indian food, brick lane is famous for it.