I have a
If it is one line of text and/or image, then it is easy to do. Just use
text-align: center; vertical-align: middle; line-height: 90px; /* the same as your div height */
that's it. If it can be multiple lines, then it is somewhat more complicated. But there are solutions on http://pmob.co.uk/ Look for "vertical align".
Since they tend to be hacks or adding complicated divs... I usually use a table with a single cell to do it... to make it as simple as possible.