This has been brought to my attention today. I see this as a huge win for Ubuntu, since, let's face it, Broadcom devices are a large part of the WiFi device ecosystem. I'm happy to see Broadcom finally publishing some of their source code, and through this helping out Linux users of all distributions get better working WiFi. I see this as a win for Ubuntu in general because it will always make me happier to see people having fewer issues with wireless devices. This also translates to less wheel-spinning with broken drivers we could not possibly fix (since they are closed source), towards more productive work on other aspects of Ubuntu... or just a better chance of fixing driver issues :)
Of course, this is a work in progress and not all Broadcom devices are currently supported by this driver, but I believe that in due time, Broadcom could become one of the golden examples we can give to hardware manufacturers on how to provide the best kind of support they can to the Linux community.
Read more about this on Slashdot, OSNews, or read the annoucement on the Linux Wireless mailing list.