Sub Menu Problem

[MPC]

I've been playing with CSS sprites. Got about half my template done up in one image file. But I am noticing differences in how they render in IE 8 vs firefox. For instance, got to mypokercorner dot com and look at my 3 icons at the top right (RSS, youtube, Twitter). In IE you see a rectangle back ground. In FF it all looks clean.

The other thing I noted was the sub menus load correclty in FF but in EI they pop up on the right, not underneath. Hover over "poker videos" for instance.

All I did was change the way images load on the template.

My css file is at xhttp://www.mypokercorner.com/wp-content/themes/thesis/custom/custom.css

I can always switch it back the the way it was. I'm just curious as to why these htings are happening, and if I can fix it, I'll stick with the sprite image for now

Thanks!