Last year I bought my daughter a Wacom Bamboo Pen CTL-460 tablet. I quickly got it working with Gimp and Inkscape on our Windows-XP PC but was unable to get it to work at all on our laptop running Ubuntu 10.04 LTS. And that was how I left it, until last week when I came across this page at the Linux Wacom site. What I hadn't been clear to me last year was that both a kernel driver (input-wacom) and a X11 driver (xf86-input-wacom) were necessary and that Ubuntu 10.04 LTS has only the X11 driver included. Last week I simply downloaded and installed the kernel driver following the given instructions and now the Bamboo Pen works perfectly on the laptop too.
Every time you update the Linux kernel you need to reinstall the Wacom kernel driver.