I have a working code here: http://jsfiddle.net/WVm5d/ (you might need to make the result window bigger to see the align center effect)
Question
Similar to @vijayscode's answer, this will horizontally center an inline-block element (but without needing to modify its parent's styles as well):
display: inline-block;
position: relative;
left: 50%; // Move the element to the left by 50% of the container's width
transform: translateX(-50%); // Calculates 50% of the element's width and moves it by that amount across the X-axis to the left