"CloudOpen Europe is a conference celebrating and exploring the open source projects, technologies and companies who make up the cloud."
It's in Edinburgh, UK, October 21-23, 2013.
They want 50-minute presentations, Bird of a Feather sessions, & 2-hour tutorials about Puppet, OpenStack, Hadoop, Chef, Gluster, filesystems, etc. The CfP closes July 21st; you'll get acceptance/rejection notification by August 1.
https://events.linuxfoundation.org/events/cloudopen-europe/program/cfp
This conference is eligible for subsidy of travel costs -- see Participation Support https://meta.wikimedia.org/wiki/Participation:Support to put in your request.