1)   Virtual Serial Port Control 2.4
Creates virtual COM ports directly from your own programs and fully control them! Provide interaction between serial communications applications and your program! OEM license allows you to distribute this ActiveX control as a part of your software

 2)   Serial Port Control 2.1
Serial Port Control is an inexpensive royalty-free component. It supports VB, VB.Net, C#, Borland Delphi, Borland Builder. Just put it on a form and you've got all the functionality you need to access an RS232 port.