gMessage is a GTK+ replacement for the xmessage program in the X distribution. It attempts to mimic that programs behaviour as closely as possible, so you can simply replace it in any script, crontab or anything you might be using it for.
This first release of gMessage uses GTK+ 1.2, I plan to add themes and GNOME support (whatever that might mean for an utility such as this) in future releases.
The man page could use some work. Perhaps I should add an info page. I'm missing basic things such as a README. Other problems are noted in the man page.
gMessage is obsolete, since it uses GTK1. There's another project, gxmessage, with the same objective and using GTK2. It's even packaged for debian!
Only source is available: gmessage-1.0.7.tar.gz