this was on the news a few days ago here is the link
we started floor time at around age 2 1/2 - 3 it worked really well to get my son engaged and teach at the same time (fine motor skills,gross motor skills,social). Right now we use ABA as my son is just about 6. I believe floor time therapy helped immensely with teaching him how to engage with others, how to make eye contact and just learn how to play. I wouldn't recommend floor time therapy as the only source of therapy but combined with other therapies you can achieve success.
my son does floortime at his preschool along with ABA and Speech Therapy...it helps i think.
Thanks for the replies. I think I'll try a combination - my daugher is turning 7 and the more I read, it seems like we may be a little bit too later in the game for floortime..