After much testing and general messing about, I have found that the mplayer-plugin for firefox works much better than the realplayer plugin (IMHO). It not only streams typical realmedia but also streams quicktime, windows media (wmv etc) and pretty much every other type of media out there. Also, you do not need the linux binary emulation to get this working.
To get the Mplayer plugin working with Firefox on FreeBSD you need to do the following:-
Install the firefox port
cd /usr/ports/www/firefox/
make install
Install mplayer
cd /usr/ports/multimedia/mplayer make install
Install mplayer plugin for firefox
cd /usr/ports/www/mplayer-plugin/
make install
This port should install mplayer files into the following directory:-
/usr/X11R6/lib/browser_plugins
Once you restart Firefox you should be able to see the registered plugins by browsing to about:plugins
Start firefox and try to stream some media - a good test is the bbc radio website which can be found here:-
Please be aware that these "howtos" are generally a work in progress so if you have any queries or recommendations then feel free to email me at:-