The easiest way at present, is to create your text on a path in Illustrator and import that into Photoshop. Or you can use PaintShop Pro. Or, if you can find an old copy of it, Extensis PhotoGraphics is a plug-in that provides the same capability.
Otherwise, buy Photoshop CS when it is released, as it will finally provide this feature.
To solve your problem immediately via a more brute force but still pretty straightforward approach, try Trevor Morris's tutorial at <
http://user.fundy.net/morris/photoshop7.shtml>
Have fun!
Daryl