Ad Alignment

In your style.css is img {padding: 10px} giving all images padding. The ad is getting pushed by padding. You might want to keep that padding on other images so cancel it out in the sidebar. Put this with your other sidebar CSS

Removes left and right padding but keeps your ads separated vertically.

.sb_onleft img{
padding:5px 0px;
}

same with right if you want them to line up

.sb_onright img{
padding:5px 0px;
}