Code deployment tools

G'day,

I'm building an application to manage WordPress PHP code on many servers. Our application will push down code updates to each server, as well as performing backups and testing.

I'm considering different methods of pushing updated code onto the individual servers. I'm considering something like Capistrano (I've no experience in Ruby though). I've also considered using subversion and then remotely calling svn commands via SSH.

Are there any other tools specifically for this purpose? The servers will have persistent data (the WordPress databases) so I don't want to re-image them every update. Plus, they will each have a different set of plugins / themes, so building many images would be too complex.

If there are any papers on code deployment, or other recommended reading, please point the links my way.

Likewise, if anyone has any suggestions, or would like more details, just let me know.

Cheers - Callum.