GD::Text::Arc is an addition to GD and GD::Text that simplifies drawing text on a curve. Sample output is here. It's not a terribly complicated module, in fact it's about 250 lines of code, but it does just what I want it to, so I'm happy. The most time-consuming part of the process was writing the 250 lines of documentation.
This was also my first foray into writing tests while I wrote code; that was just as useful as everyone says it is, so I think I'm a convert. Of course, I'm sure I need way more than 46 tests, but it's a fine first draft.
Now that I'm all puffed up with releasing my first CPAN module and stuff, I'd love for people to pick it apart and tell me what I did badly. :-)
BTW the sample image looks very neat, IMHO. No I haven't actually looked at your code (yet).