Hi Jacking, as long as you are on MAC OsX 10.4 (Tiger) and have bluetooth built in to your mac (if not you can use a Bluetooth USB dongle (i use the D-Link DBT 120)
Then go and buy one of the Jabra range of Bluetooth headsets that are used for mobile phones (thats what mine is used for too!)
All you need to do then is turn on the Macs Bluetooth in system Prefs and then PAIR the headset (you will need to put the Jabra headset into Pairing mode, just hold down the on/off button on the headset untill the led goes soild) and Mac together (again in bluetooth setup - Add a new device click on headset & follow the instructions)
When they are both paired together then open up audio prefs in Skype and choos the Jabra device as input and output.
Then you should be able to talk hands free.
Hope this helps
Cheers
Madonmacs