we did the baby signing with both our kids and neither of them really throw tantrums so to speak. We didn't get totally into it, just the basics -- basic needs plus if there was something they seemed really tuned into.
If he's just doing it for attention, then unless he's hurting himself, I'd probably just ignore it and he'll learn that sometimes mom has things she needs to do too. If he's hurting himself ask your doctor.
We also got the disney toddler games. Where they just move the mouse over the shapes and stuff and my son loved it. we've moved onto the preschool version and he's doing great with working a mouse now. He would only do the toddler thing for about 15-20 minutes by himself, but hey, that enough time to put laundry away.