Stratford International aerial photo
The Olympic Development Authority have published some amazing aerial photos of the Stratford Olympic site, including this one that shows the Stratford International DLR extension very clearly.
Here's an annotated version (click to enlarge):
You can see exactly where the track will go, taking over the North London Line route on the right and then running alongside the existing tracks on the left. They've been quietly boxing in the route at the Stratford station end, in order to build over it. The North London Line will be diverted to use new platforms parallel to the existing main line platforms, using the track along the right hand edge of the picture to get there.
This image shows a similar view but from nearer Stratford station.
[via Skyscraper City]

