Wrote an article on DevZone about migration script from php 5.2 to 5.3. This little script can save some time when you consider to move your codebase to run under 5.3 (which you should :) ).
This script doesn’t do everything I’d like it to do – specifically, I’d like to make it try to figure out all kinds of messy reference scenarios, but I’m not sure how yet. And if you have other idea, please comment there or here. It’s on public git, so you can take it and modify if you wish.