[otrs] Customisation

Hi Guys, Are there any guides for customisation when it comes to adding new fields? I want to add some fields like Phone Number and so on to the customer addition form in the Agent view (the bit where they can add a new customer). I want to be able to set it up so it is easy to get the customers phone number when you go into phone call mode. Also, how do I allow managers to see tickets even when they are locked to a consultant? I want to be able to get to tickets that are locked in cases where customers complain, etc. Cheers! ~Chris