I'd like to search for a given MAC address on my network, all from within a Python script.  I already have a map of all the active IP addresses in the network but I cannot figure out how to glean the MAC address.  Any ideas?
I don't think there is a built in way to get it from Python itself.  
My question is, how are you getting the IP information from your network?
To get it from your local machine you could parse ifconfig (unix) or ipconfig (windows) with little difficulty.
Search for host with MAC-address using Python