There are many activities on an application that need things like:

• Send email, Post to twitter
• thumbnail an image, into several sizes
• call a cron to find connected relationships

A good way to do these tasks is to write into an asynchronous queue on which operations are performed.

What django application can be used to implement such functionality, as the one Amazon Simple Queue service offers, locally?

I have come across celery. Right thing? Anything else that exists, like this?