It's really simple:
1. Use a EDIT BOX control and bind it to the field
2. In the PROPERTIES box select "Type Ahead" tab
3. Check "Enable Type Ahead"
4. Mode "Partial"
5. Suggestions - compute value:
return @DbColumn(new Array(@DbName()[0],"names.nsf"),"($VIMPeopleAndGroups)",2);
Check out this Wiki article: