Hello there Damien. :hello: Glad to have you join us here at Android Forums.
Congrats on *both* the new phones (what, are you crazy?
Here's are links to each of your phone's sub-forums here on AF, where you'll find a ton of great info, tips, and help if needed from the folks who know 'em best.
Samsung Galaxy S3 - Android Forums
Samsung Galaxy Nexus - Android Forums
That should get you started here. If you have any questions, of course feel free to ask - we're here to help.
Enjoy your time here, and happy posting!