Yes... in System Preferences > Network ... select the connection (WiFi, Ethernet, BT, etc) and click the ADVANCED button. Then go to the HARDWARE tab and you should see the MAC address at the top of that dialog box.
As pmau stated, there is a different hardware MAC address for each connection type.
Open Terminal and use the "ifconfig" command. That will show you all of the interfaces on your Mac. The MAC addresses are listed as "ether: xx:xx:xx:xx:xx:xx"