well the notes section in each contact can keep that information, at least a good portion of it. There are also other options for databases or spreadsheets out there. eoffice has an excel viewer/editor that could be able to help.
HanDbase too DDH Software
i havent personally used my costumer but it seems like (from your description) that it would work, as would the above listed app. if you have more details i might be able to help you more.