Posted on MacOSXHints on Friday, this tip help us out too. You can address the kernel panic problem that appeared for a lot of us by downgrading the USB drivers (kernel extension).
The USB kernel panic in 10.2.5 seems to be a pretty universal problem. No word from Apple yet that I can discern, except the instruction to disconnect the offending hub. However, hope is at hand. Buried in the iMac (Flat Panel) discussion group at apple.com is a comment by A. Brody that the USB kernel panic issue in 10.2.5 can be fixed by retrograding the IOUSBFamily kernel extension. You can download the IOUSBFamily installation software to install an older version of the driver.
