Either bookmark this post and you will be able to keep up with the construction of the London Aquatics center for the 2012 Olympics or just go to the site and bookmark it.
Found this originally here at about.com who links to London2012.com.
From London2012: "...Progress on the site is well underway with construction starting in July 2008, two months ahead of schedule. During the Games the Aquatics Centre will include a 50m competition pool, a 25m competition Diving pool and a 50m warm-up pool. ..."
See renderings here for the new London Aquatics Centre.
Other venue web-cams: [Link]