www.codeproject.com/KB/webforms/ClientSideTreeView.aspx

quickstarts.asp.net/QuickStartv20/aspnet/doc/ctrlref/navigation/treeview.aspx skins and styles mostly

Experimental TreeView adapter version: with postback and node selection

forums.asp.net/p/993426/1294834.aspx#1294834

Maintain ASP.NET Tree Position on Postbacks

www.codeguru.com/columns/vb/article.php/c12869

ASP.NET AJAX Maintain Scroll Position from a Partial Page Update

www.eggheadcafe.com/tutorials/aspnet/7dd57635-0587-42ba-ae73-f52449e653bf/aspnet-ajax-maintain-scr.aspx

Additional info:

Three Cures for Common Site Map Ailments

msdn.microsoft.com/en-us/magazine/cc163598.aspx

Discussian: Preserving Expand/Collapse state of TreeView across pages

forums.asp.net/t/1293934.aspx

Maintaining treeview state across your site in a master page, and no expandcollapse icons.

forums.asp.net/p/1022893/1387445.aspx