mystifier, I wasn't suggesting adding a new div and padding for it. I was suggesting adding padding to your anchor element (the links themselves). right now, if you hover over the link, there's a 1px border that pops out, which is what pushes everything away. So if you set a 1px padding on the a, and then a 0 on the a:hover, you'll basically eliminate the jumps.
FWIW, when you have 0, it is not necessary to declare the measurement unit. Also, when you have all measurements the same, you do not need to repeat them. Finally, if you're going to declare styling inline, might as well use CSS all the way ;) So your
<div align=center style="padding: 0px 0px 0px 0px">
Could have been written:
As for testing, it is indeed usualy a good idea to test in several browsers. While IE6/7 accounts for a large segment of traffic, my stats show about 35% of traffic on non-IE browsers... Over a third of all visitors are not using IE... Your choice ;)