This is a bit OT, since I have a BCM4322, but had same problem.

Upgrade to natty left wireless (BCM4322 here, see below) not working. Pressing the [fn-f6] combination lit the Wifi-LED for short time, then it switched off again. I did not find any related entries in dmesg/syslog, but:
[ 3219.579913] keyboard: can't emulate rawmode for keycode 240

reinstalling via GUI and
# dpkg-reconfigure bcmwl-kernel-source 
plus a reboot made it working again

-- 
# lspci -v
0c:00.0 Network controller: Broadcom Corporation BCM4322 802.11a/b/g/n Wireless LAN Controller (rev 01)
	Subsystem: Dell Wireless 1510 Wireless-N WLAN Mini-Card
	Flags: bus master, fast devsel, latency 0, IRQ 17
	Memory at f6dfc000 (64-bit, non-prefetchable) [size=16K]
	Capabilities: <access denied>
	Kernel driver in use: wl
	Kernel modules: wl, ssb

# hwinfo --wlan
> hal.1: read hal dataprocess 3092: arguments to dbus_move_error() were incorrect, assertion "(dest) == NULL || !dbus_error_is_set ((dest))" failed in file dbus-errors.c line 280.
This is normally a bug in some application using the D-Bus library.
libhal.c 3483 : Error unsubscribing to signals, error=The name org.freedesktop.Hal was not provided by any .service files
17: PCI c00.0: 0282 WLAN controller                             
  [Created at pci.318]
  Unique ID: JNkJ.iNX4XJgxpnF
  Parent ID: qTvu.cijBwYawYx6
  SysFS ID: /devices/pci0000:00/0000:00:1c.1/0000:0c:00.0
  SysFS BusID: 0000:0c:00.0
  Hardware Class: network
  Model: "Dell Wireless 1510 Wireless-N WLAN Mini-Card"
  Vendor: pci 0x14e4 "Broadcom"
  Device: pci 0x432b "BCM4322 802.11a/b/g/n Wireless LAN Controller"
  SubVendor: pci 0x1028 "Dell"
  SubDevice: pci 0x000d "Wireless 1510 Wireless-N WLAN Mini-Card"
  Revision: 0x01
  Driver: "wl"
  Driver Modules: "wl"
  Device File: eth1
  Features: WLAN
  Memory Range: 0xf6dfc000-0xf6dfffff (rw,non-prefetchable)
  IRQ: 17 (no events)
  HW Address: 00:25:56:11:aa:ac
  WLAN channels: 1 2 3 4 5 6 7 8 9 10 11 36 40 44 48 149 153 157 161 165
  WLAN frequencies: 2.412 2.417 2.422 2.427 2.432 2.437 2.442 2.447 2.452 2.457 2.462 5.18 5.2 5.22 5.24 5.745 5.765 5.785 5.805 5.825
  WLAN bitrates: 1 2 5.5 6 9 11 12 18 24 36 48 54
  WLAN encryption modes: WEP40 WEP104 WEP256 WEP128 TKIP CCMP
  WLAN authentication modes: open sharedkey wpa-psk wpa-eap
  Module Alias: "pci:v000014E4d0000432Bsv00001028sd0000000Dbc02sc80i00"
  Driver Info #0:
    Driver Status: ssb is not active
    Driver Activation Cmd: "modprobe ssb"
  Driver Info #1:
    Driver Status: wl is active
    Driver Activation Cmd: "modprobe wl"
  Config Status: cfg=new, avail=yes, need=no, active=unknown
  Attached to: #6 (PCI bridge)

# dmesg
[   19.425220] eth1: Broadcom BCM432b 802.11 Hybrid Wireless Controller 5.100.82.38

dpkg-reconfigure bcmwl-kernel-source 
Removing all DKMS Modules
Done.
Loading new bcmwl-5.100.82.38+bdcom DKMS files...
Building only for 2.6.38-8-generic
Building for architecture i686
Building initial module for 2.6.38-8-generic
Done.

wl.ko:
Running module version sanity check.
 - Original module
   - No original module exists within this kernel
 - Installation
   - Installing to /lib/modules/2.6.38-8-generic/updates/dkms/

depmod....

DKMS: install Completed.
update-initramfs: Generating /boot/initrd.img-2.6.38-8-generic