createprocess and pass data between it and the parent process

How do i use CreateProcess (or any other suitable function) such that my MDI parent program can call another MDI(or dialog based) executable and pass some data (such as a string) to and fro?

Application example, I create a process to run a frame grabber and it can throw a grabbed frame back to my parent process which can be an image editor. The parent should know when the created process has killed itself, but at the same time, independent of it. The parent program is still able to do other process while the frame grabber is running.