I finally decided to redesign our site using CSS (a little late? lol)

http://zeniors.org/

In firefox, there are lines under the left nav. In internet explorer, there are lines only on the bottom two, and sometimes no lines at all. If I refresh in IE, I see no lines, but if I minimize the browser and reopen it, I see a few lines, but not all.

I'm confused!

P.s. The lines are placed as the bullets for the list.

You're talking about the lines that divide the links on the left side, right?

Maybe you've fixed it by now but it looks fine to me in IE6. At the computer that I'm at right now I only have IE6 available to check, though :(

looks OK in ie6 here also, FF2 looks OK, but I see nothing but a background color in Opera 9 .?
While your at this early stage try getting your code to validate I notice your using a Strict xHTML doctype...was that intentional.?

Anyway get the page to validate now, will create a solid foundation to build on.

Tips:
html comments are closed without the ! (<!-- html comment -->).
All xhtml tags must have a closing tag single open tags like img must be closed in the following way ( <img src="image.gif" />).
in Strict, styling attributes like border="0" are not allowed.

That should set you on the right track..
Good luck

Thanks for the responses. Yup the problem was ! in the closing of the comment.

I was hoping to do strict xhtml. Is that not a good idea?

You can still do XHTML strict. Just omit the border="0" bit for the img tags and instead use the following CSS rule

img {
border:0px;
}