Ceilometer aims to deliver a unique point of contact for billing systems to acquire all counters they need to establish customer billing, across all current and future OpenStack components. The delivery of counters must be traceable and auditable. The counters must be easily extensible to support new projects, and agents doing data collections should be independent of the overall system.

(A ceilometer is an instrument that measures cloud coverage.)

Home Page: http://wiki.openstack.org/Ceilometer
Code: https://github.com/openstack/ceilometer
Tarballs: http://tarballs.openstack.org/ceilometer/
Documentation: http://docs.openstack.org/developer/ceilometer/

COMMUNITY
Meetings - http://wiki.openstack.org/Meetings/Ceilometer
Mailing Lists - http://wiki.openstack.org/MailingLists . Archives can be found at https://lists.launchpad.net/openstack/ by selecting all messages containing [Ceilometer] in the subject (or via http://www.mail-archive.com/search?l=openstack%40lists.launchpad.net&q=%5C%5BCeilometer%5C%5D ).
IRC - #openstack-ceilometer on http://freenode.net/