KB2WIG has a great recommendation, specifically:
OPERATION SERIAL NUMBER
In addition to marking your property, you need to keep
an inventory that records the make, model, serial number and
any distinguishing characteristics. To ease the inventory
process, the Fort Worth Police Department has created a
secure online database. The Voluntary Serial Number
Registration database for your personal items is available at
the Fort Worth Police Department’s Web site,
www.fortworthpd.com. If you prefer to maintain your own
inventory, remember to keep it in a secure place.