For more info about this and other Linux-compatible USB devices see the USB Survey and my Mobile USB Linux Hardware Survey .
From kernel source 2.4.4:
ADMtek AN986 Pegasus (eval. board)
ADMtek ADM8511 Pegasus II (eval. board)
Accton 10/100
Billington USB-100
Corega FEter USB-TX
MELCO/BUFFALO LUA-TX
D-Link DSB-650TX, DSB-650TX-PNA, DSB-650, DU-E10, DU-E100
Linksys USB100TX, USB10TX
LANEED Ethernet LD-USB/TX
SMC 202
SOHOware NUB Ethernet
There are many dongles around. I have made some experience with the AIRcable for laptops and PDAs (e.g. SHARP's Zaurus models SL-5x00 and C-7x0). This USB dongle kit provides a fast, convenient way of connecting mobile Linux computers to another personal computer or notebook computer or mobile phone without any cabling. The AIRcable uses a BlueTooth connection without the need to set up a complicated BlueTooth configuration. For example: The AIRcable Zaurus-USB can be used for syncing the Zaurus (ZaurusManager, Intellisync), for Qtopia desktop and for network connections through the PC (Linux, Windows and Apple) running pppd. You may find further details and a survey of compatible mobile phones etc. at TuxMobil.