Author: Joel Esler
There are two sets of rules distributed on the Snort.org web site.
The "Community Ruleset" is freely available to all users, and is licensed under the GPLv2.
The "Snort Subscriber Rule Set" will be made available to users in the following ways:
Subscribers will receive rulesets in real-time as they are released to Cisco customers - 30 days ahead of registered users
Registered users will receive rulesets 30 days after Subscribers.
Unregistered users will receive access to the community ruleset.
The rules are available for download here.