Some time ago I had set up my router, a Linksys Wireless G broadband router WRT54GL in such away that I could connect to it from my PDA, a Dell Axim x51v. After I had installed NDISwrapper on my Acer Aspire 4320 running Ubuntu I had no problem at all connecting to the router.
In the basic wireless settings tab I use the name 'cadwal', which is also the name of my development computer, as service set identifier (SSID), and I have the wireless broadcast of this identifier enabled. Some people, and even the manual that came with the Linksys router if I recall correctly, recommend to disable the broadcasting of the SSID for security reasons. However, if the security of your wireless network relies on the identifier to be "hidden" (note the quotes), something is very wrong.
Also, not broadcasting the SSID makes troubleshooting your wireless connection harder, so I recommend to enable this setting, and broadcast the SSID.
In the wireless security tab I selected WPA personal as the security mode. The reason for WPA personal instead of WPA2 personal is that the Dell Axim X51v doesn't support WPA2 as far as I know. For the same reason I selected TKIP instead of AES. Make sure that you use a strong and long pre-shared key (PSK) to increase the security of your wireless network.
In the wireless MAC filter tab I have enabled the filter, and checked "Permit only PCs listed to access". While one shouldn't rely on this adding extra security, as far as I know, I preferred to enable the MAC filter anyway. Currently there are only two entries in the filter list, one for my Dell Axim PocketPC, running Windows Mobile 5, and one for my Acer Aspire notebook running Ubuntu 7.10 (Gutsy Gibbon).
Note that enabling the MAC filter makes also might make troubleshooting harder, since one mistake in the MAC address and your computer can't connect to the wireless network. Finally, don't ever rely on MAC filtering as the sole means of securing your wireless network.
After I had set up the NDISwrapper with the right driver for my Acer notebook (AR5006EG), iwconfig showed that a wireless network was present.
When I clicked on the network applet icon, which showed an orange warning sign, I got a list of available networks, including the one provided by my Linksys WRT54GL router.
When I clicked on the radio button in front of "cadwal" a dialog window popped up in which I could enter the information required to connect to the router. Note that I choose the settings shown in the above window because that are the best, as far as I know, I can select on my Axim X51v PocketPC.
After I had clicked on the "Login to Network", the network icon changed to an animation including two green "LEDs". A short time later the bottom one turned green, and then the top one, and then the icon changed to 4 bars, a clear sign that the notebook was now connected to the wireless network.