Visual Basic - Xbee - Create Global Serial Port - to use in other forms

I am learning Visual Basic 2010, using Visual Studio 2010. I have a frmMain that has buttons to call various other forms - frmSetup, frmLapClock, frmStopWatch, etc... I would like to initialize and declare my Serial Port once (load settings from txt file), then be able to use it in all of the forms. This includes frmSetup where I can test and change to port settings if needed. While I can do this during the formLoad process of the frmMain, I cannot reopen the port in sub forms. I tried making the Serial Port public and a variety of other methods. I typically drag the serial port icon from the toolbox into the frmMain. Also tried manually setting it up by typing in the commands + setting up a separate module.

I am familiar with setting this up on one form and had success with that - many example available on the web. Any help would be greatly appreciated.