Tink,
Welcome to the world of Slack!
I just finished installing Slack 8.0 on my laptop (Gateway PIII@650) and am using a Xircom PCMCIA NIC. With the 2.2.19 kernel, I believe the tulip_cb driver was being used. It worked every other boot with my NIC. I've since upgraded to kernel 2.4.18 and am using the xircom_cb driver.
Here's a HOWTO which gives a brief rundown on setting up a PCMCIA NIC:
http://www.tldp.org/HOWTO/Laptop-HOWTO.html
There is also the PCMCIA HOWTO on the same site.
On Slack, the primary PCMCIA directory is /etc/pcmcia - the file network.opts has the settings for the network adapter.
Good luck!
j.