Here's a summary of WebParts support in ASP.NET AJAX 1.0.  There are three different WebParts features:

1. Cross-browser drag and drop.
2. Modify WebParts page (drag and drop, minimize, restore, close, add, delete) without postback.
3. Update contents of WebPart without postback.

Cross-browser drag and drop is enabled by using the WebParts controls in the AJAX Futures CTP.

Modifying a WebParts page without postback is implemented by wrapping the WebPartManager and WebPartZones in an UpdatePanel.  This was partially working in the ASP.NET AJAX July CTP, but it does not work and is not supported in ASP.NET AJAX 1.0.  It may be supported in Orcas.

Updating the contents of a WebPart without postback is implemented by placing an UpdatePanel inside a WebPart.  This is supported in the core ASP.NET AJAX Extensions 1.0.  It should work with either the ASP.NET 2.0 WebParts controls, or the AJAX Futures CTP versions of the WebParts controls.

Hope this helps,

-Mike