London - UK
Disclaimer: I'm a developer myself, I made this list out of necessity while looking for a job in London last month.
Last "Who is Hiring June 2012" didn't have any jobs in London!
<a href="http://roundabout.io" >http://roundabout.io</a>
The list is far from comprehensive, but if you're a developer in London you should definitely have a look at it, there are more than 30 startups listed, and not all of them post in this thread.
Ask HN: Who Is Hiring? (July 2012)