Which version PhotoShop?
You can warp a text layer in PhotoShop 7... I don't remember if earlier versions can. Select the text layer, click the "warp text" button, and select one of the preset warp methods from the list.
As far as using a pen path... I don't think so. I know Illustrator can easily do that.
If you can't figure it out, show me what you need and I'll draw it in Illustrator for you.