Odd, but that's one I haven't tried since my Freehand days... Couldn't come up with a quick answer for you after popping into Photoshop for a minute, but hopefully someone in-the-know will be along to share some tips.
Because Photoshop 6.0 does not have pure vector support it does not have the ability to put text on a path. (have not worked with 7.0) You can use the "Warp Text" to create an arch in PS6.0.
Mivox has the right idea. If you have an illustration software like Freehand or Illustrator use that and import the result into your PS file.