How can I use images instead of text in my menu?

How can I use images instead of text in my menu?
I need to replace the ‘log in’ and ‘home’ links as well as my ez-pages and categories.

Here is my site;
http://www.clearmagicgems.com/

Here is what Im trying to make;
http://www.clearmagicgems.com/beta/

I initially thought about making a div in the header’s php which would surround my menu, and could have a background image applied to it. I made one called ‘liquid’. The problem with this method can be seen on this site;
http://www.firestartermedia.com/

You can see that enlarging the txt size ruins the alignment of the text in the menu. I could get around this with multiple divs and background images to make the menu expandable, but this seems needlessly complicated and I am still limited by fonts.

As my site is only a small one, I think the easiest thing (and something I would like to know how to do for the future), would be to replace the text in the menu with images.

thanks
james