I just want to be more specific on managing the wireless card installation. In kernel 2.6.20, ieee80211 is build into kernel, it can not be disabled (Y by default), so there is no need to install ieee80211 module (as suggested in ipw3945 INSTALL file), although the ieee80211 installation can also be done. All you have to do is install ipw3945 driver (if it claims you have to force it, because it has found ieee80211 duplicate, just force it) and then copy the daemon file (ipw3945d) into /sbin folder. Running ipw3945d will load ipw3945 module and because ieee80211 support is build into kernel, there is no need to load ieee80211 module again, hence the error if you try to run ./load from the ipw driver directory (as suggested in INSTALLATION file). Now, you should be able to see a description of your wlan card, if you enter iwconfig command (if you don't, i don't know what to do - i compiled new kernel and it worked).
Next thing is to configure the wlan, it is enough to set essid and WEP key (if you use one):
Code:
iwconfig eth1 essid YourActualEssid
iwconfig eth1 key xxxxxxxx (where xxxxxxx is you actual hex key or s:yyyyyy, where yyyyy is your ascii key)
Once you did that, just configure eth1 (if that's recognised as your wlan card) with ifconfig:
Code:
ifconfig eth1 {$IPADDRESS} broadcast {$BCASTIP} netmask {$NETMASKIP}
route add default gw {$GWADDRESS}
(Replace variables in curly brackets with actual ip addresses!)
ifconfig command implicitly enables eth1 device, so there is no need using ifconfig eth1 up (but it can be useful when testing).
If you have more then one eth device on your laptop (what usually is the case), be sure to bring unused devices down, since that can be a cause for problems. You can do this using the command ifconfig eth0 down (replace eth0 with the identifier of your device).
To automate the process, it is enough to configure ipw3945d to start on system startup (on slackware placing ipw3945d into /etc/rc.d/rc.local). To configure wlan card via iwconfig and ifconfig, you can write your own bash script, it's really straight forward or you can use my script, which i will post when i come back to my linux machine
I hope this post will someday help someone to configure his/her intel 3945 wireless card!