So I Googled and found out how to draw an arc: http://www.php.net/manual/en/function.imagearc.php
The only problem is how do I write text $margin pixels from the arc that is curved.
Centre aligned @ $degrees.
Here is an example: http://img194.imageshack.us/img194/3667/scan0001fe.jpg
Let me know if this doesn't make sense.