I have just applied for professional membership from the BCS (British Computer Society). They are a professional body that looks over the UK IT industry. They have quite a few members (approx 65,000). Although there are other IT professional bodies (IAP and IMIS for example), I feel that the BCS represents IT a little better.
People seem to automatically think of these organisations as out to get you or out to steal your money or holding some secret meetings about mass cover ups. In reality the BCS is what people make of it. It is just a collection of professionals in the IT industry that are trying to help legislate and develop IT. The legislation side is both concerned with protecting people from fraudsters in IT and from unfair practices in IT (every has known at least one crazy IT person that has abused their powers) and also to help protect the industry (from things such as outsourcing). I in no way speak for them so these are just my ideas.
I have been to a couple of BCS meetings as I mentioned and found them to be interesting to a degree. However not enough people of my ilk attend. This is my only gripe with meetings of this type, you tend to get a lot of business facing fools talking at each other in some hope of generating business for themselves or just patting each other on the back. I think one point to make is that the BCS meetings don't really discuss relevant topics in a fast paced technologist way. As an example I went to one meeting regarding Second Life and how it could be used in business. The presentation was a little empty with no real meat in the content and by that time second life had just become a joke. If you want to do the social media thing check out the twitters, the facebooks the blogs and things like that. That said it's up to the members to direct what the meetings are about. It may be worth keeping an eye out for any interesting lectures they may hold. The one I go to is the Nottingham and Derby Branch which is in Long Eaton, Nottinghamshire.
On the subject of meetings, last week I went to a good meeting called Nott Tuesday which is held in the centre of Nottingham on a monthly basis. It is hosted by a company called Essendex (which my girlfriend works for actualy). The subject was Agile programming and so I found it really interesting, they talked about much of the things I am currently reading about in a book about extreme programming at the moment. Met some new people and had a few drinks. It completely contrasted with the meetings at the BCS in that I felt the people realy knew what they were on about and were talking about current topics. I don't know whether I learnt anything but talking about these subjects keeps it in the forefront of your mind which is where it should be!
Another set of meetings (held on a Thursday monthly) is the Axis Centre meetings, which are held through the Axis training centre in Nottingham. I am yet to attend one of these but have the feeling they may be good. The next one is next Thursday. I'll let you know how it goes if I can make it.