I've been part of an organised one, it was very busy, many non-legal queries but helping people who just didn't understand how certain things work, some more common sense helping out really and things like ringing debt collectors/ companies collecting debts to try and work out what was going to on and explain it so it was more understandable.
It is very limited as there isn't a lot you can get through, especially when there is a queue of people and it could be any kind of query coming through the door. Save very basic queries, there isn't much you can do to help in a short period (especially contentious issues and very emotive issues) and you are often asked to advise blind if people don't have documents etc... on them.
I'd maybe wonder on a liability standpoint, especially as it's a conversation more than a proper formal instruction and how it would be handled in the sense of restricting people to time and, say, one free session (of if more, the boundaries of that), say if people keep turning up wanting further advice on the same issue etc...
Maybe something to do somewhere which is not your immediate local area.
It might be much easier and less stressful to organise something via an existing organisation initially.