Try b43-openfwwf :
yum check-update && yum install b43-openfwwf
You reboot the machine and then with luck; udev should automatically load the firmware and the built in Linux driver should kick in allowing you to create a connection.
If it works you could add to the wiki entry here :
Well supported. Needs b43-openfwwf installed.
You can find out which broadcom chip you have by using :
in a console and looking through the output.
According to this :
b43-openfwwf pretty much obsoletes the proprietary driver that uses broadcom-wl so you should use it.
It says on the wiki page that b43-openfwwf needs testing, so I find it strange that it's been forgotten to be added to the alpha. Maybe you would like to report that the b43-openfwwf firmware was missing from the alpha, on the bugzilla