Cordless mouse battery level

Is there an application or package for Ubuntu 9.04 that can be added/installed that can sit permanently in the "desktop panel" that will indicate the mouse battery level.

I did have an icon appear in the panel, only once I'm sure, when the mouse battery level was reported as less than 14%, don't know where it came from and I can't seem to find it again.
I've looked in "power management" but there was nothing there that seemed useful.
My system is a desktop pc.

thanks