I've only been thinking about building and maintaining my professional network recently, mostly thanks to LinkedIn.com.
I have several jobs behind me, and I've always left on good terms. While I have asked people for references before, it was usually for the next position. Some people I've maintained contact with, but a number I have not. I'd like to approach both sets of people to see if they are willing to be references at sometime in the future. I might have a new opportunity coming up, but I don't want to limit the request to just this one.
I of course would always ask prior to giving a potential new employer their information, but how do I go about getting their general permission again? Is it best to keep it mostly professional and ask how they are doing or would that be too direct after some years of no contact?