TheServerSide.NET features 2 podcasts (10 minutes and 14 minutes) with Brad Abrams on "Patterns for successful ASP.NET AJAX Development". From the website:

TheServerSide.NET recently spoke with Microsoft's Brad Abrams to find out what he is seeing in the field and what the chefs in Redmond are cooking. Along the way he discusses patterns of AJAX frameworks, which can encompass different parts of client and server, and which may be applied in different measure by different teams.