I want to give a big thumbs up to this museum. We just happened upon it on the way driving back to DC from Ottawa. We saw all the signs and went to check it out. It's a modern interactive museum and absolutely terrific.
For more information, check the website:
The sad thing about this museum is that it is empty. It is only an hour from the chaos of Gettysburg and there is the rub. Everyone, given the choice on a package tour, goes to Gettysburg.
We spent 2 hours in the museum and especially enjoyed the vignettes on various personalities involved in the war. The personalities were followed throughout the exhibits--and they were real people.
At the end of the museum you can even interact with Lincoln and members of his official family via computer technology.
The parking at the museum is free (even extensive bus parking) but there is no food in the museum. They tried to have a restaurant but they did not have enough business to sustain it. This is a real asset to Harrisburg and a "must see" if you are in the area.