Hi,

I just tried the headset that came with my BB and it doesn't seem to work, I still hear the sound from the regular speaker. Is there anything special I need to do to enable the headset?

Shouldn't be. You should only have to plug it in and it work. At least that is what happens with my BlackBerry 8700g. Try rebooting the device if you haven't already.

Make sure that the jack is entirely inserted into the input.

I know that sometimes I'll find that it appears in, and I'll have to give it a nudge and secure it into the input before it will switch over to the headset.

If it doesn't work when pushed all the way in and after a reboot, then something is wrong with the device, hardware-wise. I'd return it.