We're currently in the process of setting up a Scaled Sitecore 7.0 environment which has a single (Content Management) CM server and two load balanced (Content Delivery) CD servers. I ran my install package on the CM server which included some custom Layouts (aspx) and custom Renderings (xslt). I noticed those didn't persist from the CM to the CDs and I was wondering what the best practice would be to accomplish this without custom software. (Team Development for Sitecore (TDS))
Thanks!
You should refer to chapter 3.4 of the Sitecore 7 Scaling Guide which will suggest you to use Microsoft Distributed File System (as Jens pointed out) or the Web Deployment Tool.
I have implemented the Web Deploy solution a few times and that works pretty good, but it can be quite difficult to setup.
The DFS solution wasn't part of the Scaling Guide the last time I had to implement file synchronisation, so I can't comment on that.