I did this tour several years ago and i thought it very interesting, it is a self guide tour as far as i remember. The brewery is just outside the centre - - on the far side of a big park ..all the tourist info centres have leaflets about it and it is a stop on the tourist buses.
Do a boat trip from Nyhavn - you get to see loads of the city whilst sitting down and drinking a beer! Dont waste your time with the little mermaid (shes very, very little). Also check out the Tivoli place - a big outdoor theme park - they have concerts and all sorts in there.
Also, Tuborg is the beer the Danes drink - and its great!
I did the tour a few years ago , it was brilliant. There was a guide and at the end there was a big hall where all the tables had national flags on them. you find your flag sit down and drink! theres bottles of all the beer carlsberg make including some unusual ones like easter beer
might have changed since i was there but it was definitly worth it. also really worth it is the ripleys believe it or not museum and the chamber of horrors in the wax musuem