Enable back button support in ASP.Net Ajax
Nikhil Kothari has updated a couple of his controls including the fantastic Update History Control in Nikhil’s own words:
This is a non-visual control that allows you to add history entries to the browser’s navigation stack selectively for some post-backs, and not for some others. This helps fix the back button to make it work, and allows you to implement Ajax patterns such as “logical navigation” and unique URLs.
There is also a cool StyledUpdatePanel control and an AnimatedUpdatePanel Control up for grabs.
Theres a load of detailed info on Nikhils blog about these controls including a video of them in action.
Without a doubt the UpdateHistory control is going to be a very valuable addition to your toolkit.