The Institute of Electrical and Electronics Engineers (IEEE) assigns an 
Organizational Unique Identifier (OUI) to manufacturers of network 
interfaces. Each interface has a Media Access Control (MAC) address of six 
bytes. The first three bytes are the OUI.

This module allows you to take a MAC address and turn it into the OUI and 
vendor information. You can, for instance, scan a network, collect MAC 
addresses, and turn those addresses into vendors. With vendor information, 
you can often guess at what you are looking at (e.g. an Apple 
product).

You can use this as a module as its individual functions, or call it as a 
script with a list of MAC addresses as arguments. The module can figure it 
out.

This module tries to persistently cache with DBM::Deep the OUI information 
so it can avoid using the network. If it cannot load DBM::Deep, it uses a 
normal hash (which is lost when the process finishes). You can preload 
this cache with the load_cache() function. So far, the module looks in the 
current working directory for a file named mac_oui.db to find the cache. I 
need to come up with a way to let the user set that location.

WWW: http://search.cpan.org/dist/Net-MAC-Vendor/