IE 8 and IE 7 compatability issues

I have a site that was designed mostly for IE 8, but we've now discovered that some of our clientele use IE 7 and even IE 6 as well. Unfortunately, because of what I'm assuming are CSS issues, these pages don't look the same in IE 7 as they do IE 8. I was wondering if th开发者_开发百科ere were any tips or things to avoid when develop a site to be cross-browser version compatible. The main problem in IE 7 is the position of items in the navigation menu. The elements seem to be pushed to the right in IE 7 when compared with IE 8.

The link for the site is here

I would love to post the html and css but I'm new and can't really figure it out. Please let me know if you need any other info. If anybody had any ideas or thoughts, they would be greatly appreciated. Thanks.

Google "ie conditional stylesheet", its a pain, but it works. Then setup some virtual machine(s) with the main targets you want to test. Alternatively, I believe that the recent versions of Visual Studio for web development ship with some tooling to see a comparison between how the different versions of IE would render a page.