Points of interest from Microsoft's ATLAS overview (a TechNet event in Ottawa):

You can have a ScriptManager on your master pages, but you need a ScriptManagerProxy if you want multiple script or service references in your content page.
http://www.nikhilk.net/AtlasScriptManager.aspx

... "Atlas" includes bridge technology that enables developers to create gateways (both declaratively and programmatically) to Web services on the Internet. Bridge code runs within the scope of an "Atlas" application, so the browser communicates exclusively with the home server.
http://atlas.asp.net/docs/atlas/doc/bridge/default.aspx

I have a working (hopefully it still works) Accordion Control on my website: http://adam.kahtava.com/professionalDev/reviews/
Read more here: http://forums.asp.net/1/1347547/ShowThread.aspx

http://atlas.asp.net/docs/Overview/debug.aspx

http://weblogs.asp.net/rchartier/archive/2005/10/06/426799.aspx

... Ajax increases the amount of XML, text or HTML network traffic. Relying on XML as the content type for request/response payloads exposes applications to Web services vulnerabilities …
http://searchwebservices.techtarget.com/originalContent/0,289142,sid26_gci1162641,00.html

http://www.nikhilk.net/
http://weblogs.asp.net/scottgu/
http://atlas.asp.net/