As you can read here, the only thing you need to do (if you have one of the old SCJP’s) is an upgrade exam (1Z0-805), focused mostly on the new bits added on Java 7. I’ve created a repository on Github with code examples that I’ve been gathering during my preparation.
I’ll upload as well at some point a pdf with some study annotations that I think may be useful to others.
I know plenty of you are very sceptical about certifications but I still think they are quite useful. If not per se, the process (meaning the study + work) you need to go through to get them it certainly is. I’ll be writing a post on this at some point as well.