Are you asking where you can get the Win98 driver for your 3c589D PCMCIA card? Try 3coms website
http://www.3com.com
As far as installing linux on it, you could just boot from cd or floppy
I use this site a lot for linux laptop info:
http://www.linux-laptop.net/
There are several pages there for the Thinkpad 600E.
Good luck. Post back if you have more questions.
- Javahead2000