A NMS is your easiest route. But if you don't have one of those just laying around you could use the Asset Discovery Tool to find the SN# and IP. Then you can just login of use SNMP. A SNMP get for ".1.3.6.1.2.1.2.2.1.6.1001" should do it.
You can get the MAC with the following OID
Name: ifPhysAddress
Type: OBJECT-TYPE
OID: 1.3.6.1.2.1.2.2.1.6
Full path: iso(1).org(3).dod(6).internet(1).mgmt(2).mib-2(1).interfaces(2).ifTable(2).ifEntry(1).ifPhysAddress(6)