I was dong a search about the old method i use to use for Drag/drop menus using divides, i happen upon another page before this one which has what you are looking for:
http://www.mattkruse.com/javascript/...ame/index.html
note: the above uses Iframes to acheive the Above a select box effect, but the author writes on the same page that select objects(ie drop down menus) may causes problems in dhtml.
personally i never had any issues, you can write some preatty sloppy jscript and html(d or otherwise) before a browser actually has a real issue, although its not recommended.
not sure if this will be any help, just posting the info for a person looking for anwsers since this might come back to me one day(internet karma perhaps

)
btw the search string i used in google was "draggable div" no quotes, that tut was hit # 5 this page was hit # 7.
heres the string
http://www.google.com/search?hl=en&i...=draggable+div
hope this helps.