I had some great questions after my session at the ISV Innovation Day in Melbourne yesterday. One was around using ASP.NET AJAX functionality in SharePoint. Completely coincidentally, Darren posted about this yesterday. He pointed to Mike Ammerlaan's great post. There was also discussion on this topic internally recently and it turns out that Eric Schoonover posted on the topic and that there's a relevant CodePlex project. Scott Guthrie also blogged about it (he also gives Darren's book a big plug in that post).