I'm using Ubuntu 10.04.4 LTS, and in my laptop there is a Broadcom BCM4312 wlan card.
lspci output:

04:00.0 Network controller: Broadcom Corporation BCM4312 802.11b/g (rev 01)
Subsystem: Broadcom Corporation Device 04b5
Flags: bus master, fast devsel, latency 0, IRQ 18
Memory at f4500000 (64-bit, non-prefetchable) [size=16K]
Capabilities: [40] Power Management version 3
Capabilities: [58] Vendor Specific Information
Capabilities: [e8] Message Signalled Interrupts: Mask- 64bit+ Queue=0/0 Enable-
Capabilities: [d0] Express Endpoint, MSI 00
Capabilities: [100] Advanced Error Reporting
Capabilities: [13c] Virtual Channel
Capabilities: [160] Device Serial Number 81-ac-1d-ff-ff-12-54-92
Capabilities: [16c] Power Budgeting
Kernel driver in use: wl
Kernel modules: wl, ssb

So as you can see, the current (and default) driver is wl - installed with jockey.
But I have another Ubuntu based distribution on my laptop (BackTrack linux), which is also 10.04, but it has the b43 driver installed and the overall performance is MUCH better. So I would like to install it on this OS too, but even google didn't help me.

So my question is how to install the latest b43 driver on my Ubuntu?