Folks, the moment you have been waiting... for VISTA users!
This is what I have discovered to make it work. If you have a copy of "OFF Phase 2", you can make it work---play the original Microsoft Combat Flight Simulator 3 online.
The main .EXE program is called "Shell.exe" under OFF Phase 2 folder. For some apparent reason, this file was somewhat modified to work for multiplaying after opening the "OFFManager"... Although, it doesn't appear modified (the date) but it is.
If you have OFF Phase 2 installed and had run it once (initialized), you can simply copy "Shell.exe" from OFF folder to your regular CFS3 folder after you have exited OFF. Click on it from there (CFS3 Folder) and you should be able to play online! Is that simple!
***Please Note. If you have recently installed "OFF Phase 2" and received this error, "0x8002801c", open Command Prompt (Run as administrator) and type "regsvr32.exe Msstdfmt.dll" (without quotes) to activate. This is needed to make OFF starts.
PM me if you have any question. Thanks and Welcome VISTA (including myself) Users!!!