library IDEAddInExpert;

uses
  ToolsApi;

//..

procedure EnumerateInstalledComponents;
var
  a,
  i: integer;
begin { EnumerateInstalledComponents }
  with BorlandIDEServices as IOTAPackageServices do
  begin
    for a := 0 to GetPackageCount-1 do
    begin
      for i := 0 to GetComponentCount(a)-1 do
      begin
        sName := GetComponentName(a, i); // name of installed component
      end; { for i }
    end; { for a }
  end; { with }
end; { EnumerateInstalledComponents }

//..

end.