How do I center list items inside a UL element?

write display:inline-block instead of float:left.

li {
        display:inline-block;
        *display:inline; /*IE7*/
        *zoom:1; /*IE7*/
        background:blue;
        color:white;
        margin-right:10px;
}

http://jsfiddle.net/3Ezx2/3/