If I have purchased games on the ps3 network store on my old ps3, how do I access them on my new ps3?
Your PSN purchases are tied to your PSN account.
By simply logging into your old PSN account on your new console, you should be able to access your past purchases.
You just have to log in with your Playstation-Network-Account and then you have acces on everything you purchased on your old PS3.
Just search for the game or whatever you want (in your PSN Store) to download and there you will see that its already purchased and downloadable.