If it's the one in the first pic below, the driver has to be backported from 2.6 kernel.http://www.oesf.org/forum/index.php?showtopic=24903
The backside shows:
Model No. USB200M ver 2.1
As far as I know, there are not any usb ethernet dongles that require a powered hub. (this means the "wired" type of ethernet dongle).
USB WiFi dongles require a powered hub because these dongles draw more power than the Zaurus USB 1.1 supplies.
I have the Belkin - F5D5050 USB 1.1 10/100 Ethernet Adapter
that works out of the box in pdaxii13.
It required some tweaking to make it work in Cacko.
I got it at RadioShack, it's shown in second pic.