http://www.rosettastone.com/homeschool-spanish
I would love to take this course. I was really disappointed when I discovered the two Spanish DS programs that Nintendo offers had "terrible " reviews. I can get by on my Spanish but I miss so much. Especially the jokes, subtle things when family and friends speaks with one another.
I would love to improve my Spanish. My daughter actually got mad at me when we first arrived in Mexico and I was speaking Spanish to her. "Stop speaking Spanish to me she shouted!" she was frustrated, but in no time at all, she was playing with the kids and picking up tons of Spanish, and her pronouciation on many words is much better than mine.
They do forget quickly though, 6 months is a long time for a 6 or 7 year old so I think the best way to educate your child and self is total immersion and for 5 or so months helps...some place where you really have to speak it to get by.
That's easier said than done because we always seem to hangout with English speakers. A good verb book really helps, and dictionary, but we travelled with neither and did fine most of the time...my Spanish is rusty but I can get by and most Mexican people are so kind and patient, so that really helps.
I have found that taking long bus rides often improved my Spanish as I was forced to communicate and that helped push thru that shyness of speaking a new language, and the fear of making mistakes and a fool of oneself. It's much easier for kids, so if you have the opportunity to immerse your child in a situation like that, I believe it will benefit them immensely later in life.