The main difference I see between IE6 and Firefox/IE7 is that in IE6 the #container with the orange border goes right down to the bottom below the right text saying "Thank You" but in FF/IE7 the border stops higher up just near "Feel free...".
You have height: 550px; in #container. Delete this and the background color and border are free to go down as far as necessary.
There is another difference between IE7 and Firefox. In FF the interstate flyover image has flipped down to a lower level. In IE7 it is on the right but the orange border cuts down half way through it. Increase the min-width of #container from 700px to 980px and the border will be to the right of the flyover image and FF should have enough space for the image. 980px also provides enough width for the Welcome to Hollywood table below.
There are other problems but is is better with the above edits.
Note that IE6 does not support min-width but seems to have created more than enough width.
Code downloaded to my PC will be deleted in due course.
WIN7; IE9, Firefox, Opera, Chrome and Safari for Windows; screen resolution usually 1366*768.
Also IE6 on W98 with 800*600 and IE8 on Vista 1440*900.