!WiFi is very flaky with my Lenovo 3000 N100.<<BR>>
I'm running Kubuntu Gutsy.<<BR>>
It uses a PRO/Wireless 3945ABG card.<<BR>>
Below are the output of some commands with a possible fix at the end.

~-{{{
$ sudo lspci -vvv
-----------------
03:00.0 Network controller: Intel Corporation PRO/Wireless 3945ABG Network Connection (rev 02)
        Subsystem: Intel Corporation Unknown device 1010
        Control: I/O- Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR+ FastB2B-
        Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- >SERR- <PERR-
        Latency: 0, Cache Line Size: 64 bytes
        Interrupt: pin A routed to IRQ 17
        Region 0: Memory at d0000000 (32-bit, non-prefetchable) [size=4K]
        Capabilities: [c8] Power Management version 2
                Flags: PMEClk- DSI+ D1- D2- AuxCurrent=0mA PME(D0+,D1-,D2-,D3hot+,D3cold+)
                Status: D0 PME-Enable- DSel=0 DScale=0 PME-
        Capabilities: [d0] Message Signalled Interrupts: Mask- 64bit+ Queue=0/0 Enable-
                Address: 0000000000000000  Data: 0000
        Capabilities: [e0] Express Legacy Endpoint IRQ 0
                Device: Supported: MaxPayload 128 bytes, PhantFunc 0, ExtTag-
                Device: Latency L0s <512ns, L1 unlimited
                Device: AtnBtn- AtnInd- PwrInd-
                Device: Errors: Correctable- Non-Fatal- Fatal- Unsupported-
                Device: RlxdOrd+ ExtTag- PhantFunc- AuxPwr- NoSnoop+
                Device: MaxPayload 128 bytes, MaxReadReq 128 bytes
                Link: Supported Speed 2.5Gb/s, Width x1, ASPM L0s L1, Port 0
                Link: Latency L0s <128ns, L1 <64us
                Link: ASPM L0s L1 Enabled RCB 64 bytes CommClk+ ExtSynch-
                Link: Speed 2.5Gb/s, Width x1


$ iwconfig > ipw3945.out
------------------------
eth1      IEEE 802.11g  ESSID:"TetraSys"
          Mode:Managed  Frequency:2.437 GHz  Access Point: 00:1A:70:87:A9:84
          Bit Rate:54 Mb/s   Tx-Power:15 dBm
          Retry limit:15   RTS thr:off   Fragment thr:off
          Power Management:off
          Link Quality=93/100  Signal level=-40 dBm  Noise level=-41 dBm
          Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0
          Tx excessive retries:0  Invalid misc:1696   Missed beacon:0


$ sudo lshw -C network >> ipw3945.out
-----------------------------------
  *-network
       description: Wireless interface
       product: PRO/Wireless 3945ABG Network Connection
       vendor: Intel Corporation
       physical id: 0
       bus info: pci@0000:03:00.0
       logical name: eth1
       version: 02
       serial: 00:18:de:0c:f7:b7
       width: 32 bits
       clock: 33MHz
       capabilities: pm msi pciexpress bus_master cap_list ethernet physical wireless
       configuration: broadcast=yes driver=ipw3945 driverversion=1.2.2mp firmware=14.2 1:0 () ip=192.168.2.103 latency=0 link=yes module=ipw3945 multicast=yes wireless=IEEE 802.11g
  *-network
       description: Ethernet interface
       product: RTL-8139/8139C/8139C+
       vendor: Realtek Semiconductor Co., Ltd.
       physical id: 1
       bus info: pci@0000:05:01.0
       logical name: eth0
       version: 10
       serial: 00:0f:b0:cc:2f:1d
       size: 10MB/s
       capacity: 100MB/s
       width: 32 bits
       clock: 33MHz
       capabilities: pm bus_master cap_list ethernet physical tp mii 10bt 10bt-fd 100bt 100bt-fd autonegotiation
       configuration: autonegotiation=on broadcast=yes driver=8139too driverversion=0.9.28 duplex=half latency=64 link=no maxlatency=64 mingnt=32 module=8139too multicast=yes port=MII speed=10MB/s


$ iwlist eth1 scan
------------------
eth1      Scan completed :
          Cell 01 - Address: 00:1A:70:87:A9:84
                    ESSID:"TetraSys"
                    Protocol:IEEE 802.11bg
                    Mode:Master
                    Channel:6
                    Frequency:2.437 GHz (Channel 6)
                    Encryption key:on
                    Bit Rates:1 Mb/s; 2 Mb/s; 5.5 Mb/s; 6 Mb/s; 9 Mb/s
                              11 Mb/s; 12 Mb/s; 18 Mb/s; 24 Mb/s; 36 Mb/s
                              48 Mb/s; 54 Mb/s
                    Quality=96/100  Signal level=-32 dBm  Noise level=-32 dBm
                    IE: WPA Version 1
                        Group Cipher : WEP-40
                        Pairwise Ciphers (1) : WEP-40
                        Authentication Suites (1) : PSK
                    Extra: Last beacon: 12ms ago


## TRY THIS ##
$ sudo nano /etc/modprobe.d/blacklist

Add Lines

#still trying to fix the gd wireless (or some other comment so you rememberwhy it was done)
blacklist ipv6
}}}-~