Applying AJAX on Dropdownlist / AJAX Tutorials

http://www.123aspx.com/redir.aspx?res=33272

http://www.dotnetspider.com/qa/Question126125.aspx

http://www.codeproject.com/KB/ajax/magicajax.aspx?fid=216309&df=90&mpp=25&noise=3&sort=Position&view=Quick&fr=126&select=1250201

http://www.codeproject.com/KB/custom-controls/ajaxdropdownlist.aspx

http://bytes.com/howtos.php

http://www.asp.net/ajax/ajaxcontroltoolkit/samples/CascadingDropDown/CascadingDropDown.aspx

http://roshanbh.com.np/2007/12/change-dropdown-list-options-values-from-database-with-ajax-and-php.html

http://www.daniweb.com/forums/thread109891.html

http://www.asp.net/ajax/ajaxcontroltoolkit/samples/Walkthrough/CCDWithDB.aspx

http://www.codeplex.com/AtlasControlToolkit/Release/ProjectReleases.aspx?ReleaseId=11121

http://www.asp.net/learn/videos/video-77.aspx

http://www.asp.net/ajax/documentation/