I have command-line program that \"do a lot of work\" and produce \"a lot of statistics\". It\'s stocks trading software pretty critical to delays, bugs, and whatever, so I don\
You can use any form of IPC (inter-process communication).
Since you're planning to go over the network in the future, I recommend WCF. If the GUI program isn't .NET, then you may need to use a lower-level solution, such as named pipes or sockets.