Guide to automatic backup of WordPress site(s)?

Ive started to acquire quite a bit of sites and it would be hassle to manually backup 50+ sites somewhat regularly. Is there any way to setup a system that backs up the files I need to be able to recoup a site that has (for some reason) gone lost?
I am guessing I need to backup databases and themes. Anyway to do this automatically and to get it to upload to dropbox or somewhere I please? Anyone have some tips or links to some guides on how to set something like this up?

See original post by Melloweitsj