Compile the package, install and reboot. Start or install Wicd as the preferred network manager in Slackware if you haven't already. Be aware that your interface may not show up or be mislabelled. For example I did not have an entry under wireless connection, and it is often suggested that the driver would create a wlan0 interface. It does not, at least not on this machine. I had to add an entry eth1 in Preferences, Wireless interface, eth0 being the wired connection, for networks to show up. This is a common problem. People think the driver is not loaded or not working when in fact it is just addressing the wrong interface. That's it, no blacklisting of other modules needed.
An alternative way of getting Broadcom wireless is detailed here on Althaf's Journal. He just copied the firmware to /lib/firmware/brcm but it looks like he recompiled his kernel prior to that. If not then this way may be even easier.
Take care-
