For simple projects, it is suffice enough to use subversion to synchronise theme/plugin code between team’s WordPress installations. However, with larger projects, in which themes/plugins are content dependent, content needs to be synchronised as well. Is there a way to do it automatically instead of using Import / Export tools from WordPress?
How to develop wordpress site collaboratively?
You can set this plugin to an hourly backup: http://wordpress.org/extend/plugins/wp-db-backup. It can send backups to email, save them on server or download them on your machine (if done manually). Content is saving its revisions anyway so I don’t think you’ll have problems with that.
SVN for the files sounds actually pretty neat, even without having other people working on your WordPress installation, but can you install svn client on a shared hosting? If you got a server of your own, this won’t be an issue for you.
Hope this helps you a bit!