Congestion charging, used appropriately, is a good idea.
The first place in the country to introduce congestion charging was Durham City, about a year before the much publicised London (yes, contrary to what the BBC thinks, there is life outside the South East).
It was introduced to reduce traffic travelling through very narrow single carriageway streets up to the Cathedral and Castle world heritage site.
It is free to enter the zone, but in order to get out, you have to pass through a car park style barrier into which you have to place £2. The charging applies between 10am and 4pm. The money raised from the scheme was intended to pay for a number of 15 seater buses which now run up to the cathedral.
The scheme has been so successful in cutting traffic into the zone that the money raised from the £2 charge no longer covers the cost of providing the buses - leaving the council with a headache of how to pay for the buses. Residents no longer have to dodge traffic in the narrow streest.
OK, this is all very small scale, but it proves that when properly thought out (i.e. it is obvious you are entering the zone, and it is easy to pay - you have to to get out!) and the money raised by the charge is ploughed back into public transport, it can work.