I am the son of an SLP here in the states and a patient of hers as well. This was a fortunate situation for me because I got good therapy and I had parents that were involved. No software will ever replace good therapy with a good therapist / pathologist.
That being said, there are video and board games to be used as therapy tools and they are all geared toward children from preschool through high school. I created a video game about a year ago for just this purpose. The games require the player to get a speech bubble which cues a visual and auditory stimulus, then the player should repeat the stimulus with their best effort. You can even use it with a microphone so that the game continues after you say the word. It does not, however, do any speech recognition, just merely detecting audio activity.
You can download a small demo (Flash projector, demo is Win only but the game is Win / Mac) at the website,
http://www.2galsspeechproducts.com/
Feel free to contact me directly if needed. leetrout _at_ gmail _dot_ com