Just upgraded to Firefox 3.5 and I have to test out the goods.
If your on a cutting edge browser the text should appear sideways. I had to tweak a bit to get it to display properly, so obviously there are a few bugs or misconceptions. The code for the curious is:
<span style="-webkit-transform: rotate(-90deg); -moz-transform: rotate(-90deg);">Sideways Text</span>