Updating a DataBound DataGridView?

I have a DataBound DataGridView in which all updates will take place in the grid itself. I've never done this before so I'm not sure how to do it. I've been googling it and haven't had much luck. Each cell is able to receive input and I have added a Button Column at the end of each row. This is where I plan to do all the I/O (add, update). Can someone show me some code or point to a link that explains how to do this?

Thanks,