Text on Curve in GIMP

Taken from GIMP Plug in Resgistry (here)

1. make a circular selection
2. select - to path (very bottom)
3. type your text then while its selected press text along path (in tool options)
4. go to the paths dialog and right click the selection that appears to be words in a circle and select path to selection

If text seems deformed:

You
probably have your text size exceeding the path length, which will
cause text to deform. Try either, stretching out the path a little bit
at a time using the Path tool, or reducing the size of the font until it
fits nicely.

In either case, you will need to make adjustments
if you want your font to be larger than it is by increasing the size of
the circle (if its text in a circular path) or making the path longer,
if its open-ended (not a circle).

To do text the other way:

Take the path and do a horizontal flip on it, and the text wraps around it the other way.