A similar question was asked before probably about six months ago.
From memory, I understand that there are two versions of the ODBC link from access to Sage, one you have to pay for and I think it is quite expensive.
The other thing to remember is that you have to be careful, you can't just update ones sage table, there may be other tables linked to it, dependent on it that you have to update as well.
It is usually a job for a Sage approved programmer.