Well, I've made some progress. Carl you were right, in the end the elusive width property was to blame after all. I found the specific culprit in the menu_ie.css file. There were seven possibilities and I narrowed it down to: ul#cssmw li span a
Ray; I went ahead and used an absolute link for the conditional ie6 global style sheet, so no matter where you are in the site the link is correct.
So my menu is now displaying horizontal, but I am still having 2 issues.
1. The text "For appointments call..." is not a link; I have separate css rules that control it's appearance and it looks fine in all browsers I've checked except IE6--- which will display it fine at first, but then reverts to an un-styled state. I have completely stripped test.php down if you want to see a version without all the other code. I believe it is the javascript file menu.js that is somehow interfering, but I don't know enough about javascript to be sure or trouble shoot it.
2. If I am on any of the pages listed under "About ACA" I am unable to mouse over either of the two drop down menus. If I am currently on one of the pages listed under "Online Store" I don't have any problems. This problem is only in IE6.
Thanks for the help guys, and if you can think of any other suggestions I'd be grateful:-)
Cheers!
Jules