I use an old Wacom Graphire instead of a mouse on my workstation. I've done this for years, and I find it really helps my wrists. It's worked fine as an absolute-mode mouse while in Linux, but it's always been lacking the pressure-sensitivity controls.

Last night I upgraded the machine to the 2.6.22 kernel, and when the tablet stopped working, I looked up the latest Gentoo Wacom How To. There's a new kernel module, and when I built that, set up the udev rule and re-enabled the Wacom input drivers in xorg.conf, I suddenly had the pressure-sensitive operation.

Right-click seems a bit messed up (it's firing on button-down, rather than button-up now, which means you can only ever choose the first option in a context menu).

[Update] Actually, it looks like the tablet is just configured differently in this mode, the pen-barrel rocker button is now left-click-front and right-click-back instead of right-click-front and middle-click-back. Probably just a setting somewhere. Okay, found it, in the "stylus" InputDevice section just add these lines:

    Option        "Button1"      "1"
    Option        "Button2"      "3"
    Option        "Button3"      "2"