I have not been able to get WPA to work between my TP T41 internal wifi
and an Actiontec DSL gateway.  WEP is working without problems.
  

I copied the profile for WEP to another WPA profile and changed the
security settings only  to 'WiFi Protected Access (WPA2-PSK)' and
entered a preshared key.  I then changed the DLS gateway to WPA with
the same key.  When I try to activate the WPA profile I usually get an
icon with red bars indicating that it is connected but out of range. The T41 is 2 feet from the DSL gateway.  Occasionally I get an icon
with green bars indicating a strong signal.  In either case, I cannot
communicate over wifi with WPA enabled even though the routing and IP
addresses are correctly assigned.
  

I did try 'WiFi Protected Access (WPA-PSK)'  but just got a 'searching
for connection' icon.
  

Other issues:
1)  I am occasionally getting a trap e when trying to activate the WPA
profiles.  This may or may not be related to the fact that I have
Object Desktop installed as, once, the system trapped when I opened the
Tab Launchbar with the WEP profile active.
  

2) I still need to use a script when switching between a wifi and a
wired connection.  This is because when using the method described in
the manual, the configuration for lan0(1) are not completely deleted
when switching to lan1(0)
  

3) Netbios over TCP/IP does not start is I follow the instructions for
configuring setup.cmd for networks that switch between a wifi and wired
connection.  The instructions state that the wifi lan configuration
should not be in setup.cmd, rather left to XWLAN.  I have found that I
need both LAN0 (wifi) and LAN1 (wired) configured.  I put in a 'dummy'
ip address for LAN1, so that both subnets are present when the system
starts.  This may be needed because, in config.sys, a tcpbeui protocol
is run after the call to run setup.cmd:

CALL=E:\OS2\CMD.EXE /Q /C E:\MPTN\BIN\MPTSTART.CMD >NUL
RUN=E:\IBMCOM\PROTOCOL\NBTCP.EXE

Note:  once the system is running, then lan0(1) can be deleted when
switching between lan1(0).