VB/Delphi "kind of" Service Program_DLL

[Antonio Fernandez-Vicenti <afvaiv@xxxxxxxxxxxxxx>]

 Customer is using Access/2003 for several apps. Several of them start 
asking for something like "Enter Customer Number", so we'd like to just 
implement such a Function just once and have all initial Forms for each 
app, when users is promted for "enter CustomerNo" either answer with a 
number (if he knows it) or , else, press F4 (or whatever, or a Button) 
to "call a Function" that will do the work: e.g. present a new Form 
asking for key values (LastName starting chars, FirstName starting 
chars, CityAreaCode, etc. Then show customers that fulfill those 
requirements, allow for selection of one of them , ... just to return 
the selected code or a "not found" value... to the original App.

Such a Function would be used throughout in several different Apps. I 
think one (best one???) of the alternatives would be to develop a 
"CustomerSelect Function, receiving no-parms, returning one integer(or 
zero, maybe) value of selected CustomerCode.
This Function could/should be writen either in VB or Delphi, then create 
a  .DLL with that Function, to register under Windows, to be used for 
any VB projects that need it.
I think of it as a "ServiceProgram" in RPG... but as a DLL.

Anyone out there willing to share an example (either VB and/or Delphi) 
of such a Function?
TIA

Antonio Fernandez-Vicenti
afvaiv@xxxxxxxxxxxxxx