I have a similar issue. Laptop is ASUS C90S running 64-bit Ubuntu 10.04 with GeForce 8600M GT and 195.36.24 driver. With external monitor in "Separate X screen", mousepad cursor gets trapped as soon as it's moved to the external monitor desktop. Oddly, my wireless mouse, when it's working (flaky bluetooth support!) moves effortlessly between desktops.
I have a similar issue. Laptop is ASUS C90S running 64-bit Ubuntu 10.04 with GeForce 8600M GT and 195.36.24 driver. With external monitor in "Separate X screen", mousepad cursor gets trapped as soon as it's moved to the external monitor desktop. Oddly, my wireless mouse, when it's working (flaky bluetooth support!) moves effortlessly between desktops.