MacLookup allows you to find the manufacturer or vendor of a computer or network card. Entering the first 6 digits of this unique number (called a MAC address or ethernet address) will allow you to track down devices on your wired or wireless network.
The database is stored locally, so no network connection is required to do a lookup.
The latest manufacturer codes from the IEEE have been imported, and the app will download updated information on every launch if connected to a network.