DS was circumcised when he was 6 for same reasons as your ds, tomwill.
The op itself was so quick he hardly seemed to be in there at all. It's horrible seeing your child anaesthetized - it was my 3rd time with ds but still hit me hard (and I'm pretty pragmatic about such things) - so don't be surprised if you seem to react more strongly than you thought you would - the staff expect it and will look after you!
He had the op in the morning and went home that afternoon. They like your child to have had a drink, a meal and a pee before they let them go home.
Afterwards he was a bit sore and didn't want to look at it, but peeing was fine (we let him pee in the bath at first - much more soothing!). It was the pulling up and down of his trousers rather than the actual peeing that worried him most.
He lived in baggy tracksuit bottoms and no underpants for a week or so, and was a bit 'sensitive' for quite a while, but he healed very quickly, and we didn't need to use any creams or anything.
The main side-effect was that, for months, he wouldn't look at his winky (family name for it - sorry if it's a bit cutesy!), as he thought it looked strange. We were very matter-of-fact and reassuring about it, but he did get a bit tearful sometimes and wish it was like it 'used to be in the olden days' , although he also freely admitted that it 'behaved' much better after the op. We were starting to wonder what to do about it, when one day he just shouted from his room, 'Mummy ! I'm looking at my winky!' - cue lots of hugs and a big treat, and after that he was fine - and he still is.
I'm really glad we had it done and so is he now. Hope this reassures you a bit