Celery is an open source asynchronous task queue/job queue based on distributed
message passing. It is focused on real-time operation, but supports scheduling
as well.

The execution units, called tasks, are executed concurrently on one
or more worker nodes. Tasks can execute asynchronously (in the
background) or synchronously (wait until ready).

Celery is written in Python, but the protocol can be implemented
in any language. It can also operate with other languages using
webhooks.

The recommended message broker is RabbitMQ, but limited support for Redis,
Beanstalk, MongoDB, CouchDB, and databases (using SQLAlchemy or the Django
ORM) is also available.

WWW:   http://pypi.python.org/pypi/celery/