The site is really coming on...
A couple of points:
1) You should probably add a "Home" Link to you left menu (I eventually found a way to get back to the home page by clicking the logo but it should be easier)
2) On the about us page the images are not aligned correctly with the text. try experimenting with using the 'align="left" ' (or right) on the img tag. You will probably need to move the text and image into one DIV to make this work
3) As for the IE6 issues it looks to be caused by the left menu bar being too wide, I haven't really looked any further than that. To be honest with you I wouldn't stress too much about IE6. IE8 is due for release pretty soon and as far as I'm concerned (and I hope the idea catches on), I'm only going to support one major release down on IE. Get the site how you want it in IE7 and FF and if you have the time/energy then worry about IE6
4) If you are seeing the old version of the site on IE6 it's probably because of your cache, try refreshing the page and if that doesn't work select "Tools" from the top menu, go to internet options and "delete files". This will clear you cache and you should be OK.
<a [B]title="About Us"[/B] onmouseover="MM_swapImage('aboutus','','Images/link_images/aboutus1.gif',1)" onmouseout="MM_swapImgRestore()" href="aboutus.html">