I agree with specialmom. Particularly about disciplining him at home. At this age it is not effective. What is effective is practicing at home when to talk or not. It will carry over to school. Classic rule is "don't interrupt". It will take time and effort, but if he can do that at home - he will be able to do that at school.
There are also several neat books in the "Learning to get along series". They are pitched a bit below his level (aimed at 4 to 7), but it might be worth getting one and giving it a try. I would suggest "Share and take turns" found here - http://www.amazon.com/Share-Take-Turns-Learning-Along/dp/1575421240/ref=pd_sim_b_6
If you/he like it - you will find several more listed on the link I gave you. If nothing else they provide a way to talk about whats going on.
I also wonder a bit about the experience level of the teacher. I have had many talkers in class and never asked for parent help because I knew that I was the one that had to deal with it.
Hi there. I have a boy in second grade and one in first and spend a lot of time in their classrooms. Wow, they are busy places and can get out of hand easily. I've noticed that different teachers also have different levels of acceptance for things like chit chat. Some want near silence which can be a lot to expect. However, I will tell you that I witness first hand when a particular child is talking when they aren't suppose to be and there are a number of reasons why it is good to help your son with this. First, their peers get annoyed with them. No one wants to sit by someone who is talking a lot if they want to get their work done and they are being disturbed. I've seen this in both of my kids classes---- peers complaining that so and so won't stop talking and they can't concentrate. It also can be difficult if the teacher is trying to go over a lesson and someone is not paying attention by talking . . . because that means at least two kids (the child who likes to talk and the one who is sitting by them) aren't listening. It can be frustrating.
Here is what I'd do. First, don't punish him at home as kids of this age need immediate discpline for it to work. And I see this not really as a 'he's bad" kind of thing but that he needs to fine tune when and where he talks. If it could be explained to him by you about peers and how they would like to hear the teacher and do their work and he should respect that . . . and if he wants to talk to his peers, that you will have play dates and perhaps the teacher could have a bit of unstructured time for working at desks and perhaps whispering to one another, he could 'hold himself' back from talking until then.
Our school uses a voice volume system which really seems to help kids. It is a one to five scale and goes like this--- 5 is emergency voice "fire", 4 is the outside, loud recess type of voice, 3 is the normal speaking voice, 2 is whispering and 1 is silent. You could also talk to him about how if the teacher is talking, that is always a 1. Then the teacher may give the class a 1 or a 2 voice volume for working on something at their desks. But he'll soon have a 4 voice volume at recess and then a 3 voice volume at lunch,.
I think in the early elementary years you have kids that are adjusting to the whole school experience and learning the boundaries is harder for some than others. he'll get it----- just help him understand the boundaries. Again, displine after school won't help at this age---- but talking about it patiently and helping him 'learn' will. good luck