I can show you tutorials for a current page using images here:-
http://www.wickham43.net/highlighthome.php
The first two examples only use background-color, so look at the third example for a CSS solution or the fourth for a PHP solution.
I haven't used a sprite, I used separate images, but it's simple to edit that.
Everywhere that I have an image url in teh styles, like
Code:
background:url(images/navbuttongreen.gif) no-repeat 0px 0px;
or
Code:
background:url(images/navbuttonorange.jpg) no-repeat 0px 0px;
you would use one sprite image. You need an image with the normal situation on the left with the visited and hover states underneath and on the right you need the current page situation with visited and hover underneath, so it would be like
http://www.wickham43.net/images/menuhomecombined.gif but with the three current page bits added to the right.
In the code above 0px 0px; is the x position and y position, so you edit the y to move the background up or down for the visted and hover states and edit the x to set the current page positions, so current page visited and current page hover would have both x and y different from 0.
Leave out the background-color from the styles if you don't have text over the background-images, or have the text off-screen.
Code downloaded to my PC will be deleted in due course.
WIN7; IE9, Firefox, Opera, Chrome and Safari for Windows; screen resolution usually 1366*768.
Also IE6 on W98 with 800*600 and IE8 on Vista 1440*900.