I'm brand new to Ubuntu, and I really love it so far, but one issue I have encountered is that my WLAN is disconnecting about every 5-10 minutes. Often times the connection is repaired automatically, but sometimes the network manager will repeatedly reject my encryption key (which of course is correct). Occasionally after a disconnect, the wireless network fails to show up at all. The only way I can solve this seems to be by completely restarting Ubuntu or connecting with a USB wireless adapter. I am using WPA/WPA2 encryption, which I've read can cause problems with network-manager, but I experience the exact same issues with WICD. I should probably note that I've not experienced any of these issues using Windows 7 on my other partition. I have a hunch that there may be a better driver out there for my card, but I have no idea how to go about searching for it or installing it. Any help would be really appreciated!

lsb_release -a

No LSB modules are available.
Distributor ID: Ubuntu
Description:    Ubuntu 11.10
Release:    11.10
Codename:   oneiric

lspci -nnk

09:00.0 Ethernet controller [0200]: Broadcom Corporation NetXtreme BCM5752 Gigabit Ethernet PCI Express [14e4:1600] (rev 02)
        Subsystem: Dell Device [1028:0201]
        Kernel driver in use: tg3
        Kernel modules: tg3
0c:00.0 Network controller [0280]: Intel Corporation PRO/Wireless 3945ABG [Golan] Network Connection [8086:4222] (rev 02)
        Subsystem: Intel Corporation Device [8086:1020]
        Kernel driver in use: iwl3945
        Kernel modules: iwl3945

rfkill list

0: phy0: Wireless LAN
        Soft blocked: no
        Hard blocked: no
2: dell-wifi: Wireless LAN
        Soft blocked: no
        Hard blocked: no
3: dell-bluetooth: Bluetooth
        Soft blocked: yes
        Hard blocked: no