This is more the function of a contacts management program. I know of some places where a database has been specifically written to record every contact with a client - phone, in person, email, letter, with dates, times, comments etc. It can get very involved. There are some ready-made apps - Act! or Maximizer I think allow you to record those sorts of fields. And no doubt there are heaps of other programs around more suitable for a legal practice.
Good luck in your research.