Viewing Problem in IE…

I use Firefox and it’s come to my attention that my blog http://thegalleyboys.com looks terrible in Internet Explorer because the sidebars and the widgets contained in them don’t display properly. It’s difficult to describe the problem but it’s quite obvious when viewing the page. Can anyone offer advice on this? It is also showing a little white bar in firefox that goes out a bit onto the backdrop.

I would also welcome advice about cross-browser compatibility in general as I only ever use Firefox and have very little idea how the site might look to users such as safari or mac users…

Thanks! and looking forward to your help.
Ryan