There are not many PCMCIA ethernet cards that work with the HP palmtops due to the low power PCMCIA slot and MS-DOS 5.0.
However, a model that reportedly works fine is the Sohoware ND5120. Another one would be the Accton PCMCIA card.
You also need some software:
1. LXCIC - an I/O card enabler.
http://hplx.pgdn.de/
2. Ethernet packet driver.
http://sourceforge.net/projects/rwhitby ... ivers/1.0/
3. some programs to use ethernet. For example mTCP which offers nearly everyting from FTP client, webserver, telnet, etc.
http://www.brutman.com/mTCP/
Or maybe www/LX, the most impressive webbrowser ever (From an MS-DOS CGA palmtop view). Was originally 99 USD, but is now freeware, so definitely a must have...
http://www.dasoft.com/WWW/wv3.htm