I have been using wmbutton for quite some time, and I think it's really nice. One thing that has always sucked was the need to recompile just to change the images. So I got the source code of the wmbutton Debian package and added the capability to change the images without a recompile. One day later I discovered that someone (ehflora) had already done this. I got his version and it looked a bit better then mine. While playing around I noticed that wmbutton was leaking memory, so I ran valgrind on it, which confirmed my suspicions. I fixed the Leaks and did some more code cleanup.
I've increased the version number to 0.6. The code is still quite a mess, but at least it's better then before. Feel free to further improve it if you like, there's plenty room for it ;-).
This program is released under the GPL version 2. A copy of the license may be obtained at http://www.gnu.org/licenses/gpl.txt.
Screenshots and more can be found at: http://www.dockapps.org/file.php/id/241
wmbutton is available directly from Debian. Check out the package page.