So it sounds like all you need to do is install ndiswrapper, install the driver and configure. First install ndiswrapper. The rest will come later. Have you already installed the 2.6 kernel which is on the second Slackware CD? If so, did you also install the kernel sources from the second CD? This will need to be done before continuing. Once done...
Laptop: Toshiba L10-154
* Chipset: Linksys, A Division of Cisco Systems [AirConn] INPROCOMM IPN 2220 Wireless LAN Adapter (rev 01)
* pciid: 17FE:2220
* Driver: On Toshiba Driver&Utilities CD (AMBIT/Winxp/neti2220.inf)
* Other: Using stable ndiswrapper-1.15, WEP is working, have to test WPA, until now no noticeable problems. Ndiswrapper Configuration File created by ndiswrapper-1.15: 17FE:2220:1468:0310.5.conf.