Vertically centering in CSS is not necessary simple to achieve as one would think. However saying this I have been able to achieve vertically centering without hacks and works in Mozilla Firefox, IE 5.5, IE 6, IE 7, Opera 9.10 and Safari for Windows.

Use vertical-align: middle with line-height. Make the line height is the same as the box height. If you do not see the alignment change make sure you have the height and line-height value set the same for the box in conjunction with the element you want to have the content vertically centered to.

Example

Source: Ten CSS Tricks You May Not Know – 8. Vertically aligning with CSS
Source: Jakpsatweb – Vertical Centering in CSS