Agree with Blueberry, there are no real wrong or right ways. I slept on the sofa next to the box and just tried to offer as much comfort as I could, - T shirts, ticking clocks, soft music are all good ideas. It is hard and its breaks your heart to hear them cry, I don't think having him on the sofa with you will do any real harm but I'd really only let him do it for a couple of nights and then try and set up a bedtime routine and be consistent, they learn amazingly quickly what to expect of you and what you expect of them and feel happier in a routine.
This time last year, I was going through the exact same thing but it passes very quickly and he'll be sleeping through, before you know it!
Best of Luck - lookforward to pictures!