I see that when you ran the iwconfig command you received the following output.
lo no wireless extensions.
eth0 no wireless extensions.
wmaster0 no wireless extensions.
eth1 IEEE 802.11a ESSID:"" Nickname:""
Mode:Managed Channel:0 Access Point: Not-Associated
Retry min limit:7 RTS thr:off Fragment thr=2346 B
Link Quality:0 Signal level:0 Noise level:0
Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0
Tx excessive retries:0 Invalid misc:0 Missed beacon:0
You have both the wmaster0 interface and the eth1 interface. The wmaster0 interface belongs to the iwl3945 driver but is not the interface used to connect to the internet. The eth1 interface is most likely the ipw3945 driver. This is telling me that you have both the iwl3945 and the ipw3945 driver loaded, assuming that you don't have any other wireless cards connected to your computer. These two drivers may be conflicting with each other and so you are not able to use network manager to get online. Try running the following command and post the output. The following is my output with some slight modifications.
# ifconfig -a
eth0 Link encap:Ethernet HWaddr BB:CC:CC:CC:CC:CC
UP BROADCAST MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
RX bytes:0 (0.0 B) TX bytes:0 (0.0 B)
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:1275 errors:0 dropped:0 overruns:0 frame:0
TX packets:1275 errors:0 dropped:0 overruns:0 carrier:0
RX bytes:1093164 (1.0 MiB) TX bytes:1093164 (1.0 MiB)
wlan0 Link encap:Ethernet HWaddr AA:AA:AA:AA:AA:AA
inet addr:192.168.1.138 Bcast:192.168.1.255 Mask:255.255.255.0
UP BROADCAST NOTRAILERS RUNNING MULTICAST MTU:1500 Metric:1
RX packets:738103 errors:0 dropped:43534 overruns:0 frame:0
TX packets:628520 errors:0 dropped:0 overruns:0 carrier:0
RX bytes:704800191 (672.1 MiB) TX bytes:114162989 (108.8 MiB)
Interrupt:17 Base address:0xe000 Memory:88000000-88000fff
By running the previous command you should now see that a new interface has shown up called wlan0. wlan0 is the interface used to connect to the internet for the iwl3945 driver. In my case I'm using the 126.96.36.199 custom kernel with the now deprecated ipw3945 drivers. I'm only using the older drivers because I've noticed a 10x decrease in my upload data transfers via FTP on the new iwl3945 drivers. I will try them out again if I upgrade to a new kernel and see better performance.
Also, just for the sake of getting more info you might want to try running the following commands to see if there are any output.
# lsmod | grep ipw3945
# lsmod | grep iwl3945
If either of those commands show any output then the modules are loaded. If no data shows up then the module is not loaded.