It took nearly two minutes for complete load on narrowband, which includes the pop ups.
The reasons are you have more images than you can shake a stick at which your underlying code is set to pre-load and use for image swapping effects, mostly with the 'on Mouse' command.
They may look nice and in your case they do, but the hit on page load speeds is vast.
There is no quick and easy answer to alter the page for more resolutions. If your images are displayed as a fixed size, you either have to select a smaller size manually or start applying percentage values to your page for all elements.
Try removing the images from a working copy of your page on your hard drive then setting the table sizes to 95% page width. If you increase or reduce the size of your browser window, you will see that your table shrinks and grows to fill that specified 95% page width, no matter which resolution you are using.
From then you can experiment with point sizes for fonts and image sizes for you graphics and buttons.
I can't really be more specific because you have so much going on in the one page there is just too much ground to cover for initial suggestions.
I'd say you have an ideal page to link to if you had an introductory page that offered a broadband and narrowband choice of site options. Broadband users wouldn't even bat an eye at the page as it stands. Narrowband users, unless they are vastly keen on the site subject, will click close and go somewhere else rather than wait a couple of minutes for your page to load.