So from what I understand Life and Limb makes your forests into creature. So are you're forests then affected by summoning sickness, and therefore you are unable to be tapped for mana the turn you play them? If so is there a reasonable to animate you're opponents land like this to set them back?
They'll have summoning Sickness. So if your opponent is also in Green, you will set them back if all they have are forests to play.
From the Gatherer Rulings page:
Forests that enter the battlefield while Life and Limb is on the battlefield will enter the battlefield as creatures. They'll have summoning Sickness.
Yes, land creatures will have summoning sickness.
Every one of your creatures that you didn't control all the time since your most recent turn began have summoning sickness, even if they weren't creatures all the time. Since a land's mana ability requires tapping, that ability can't be used in that case.
302.6. A creature’s activated ability with the tap symbol or the untap symbol in its activation cost can’t be activated unless the creature has been under its controller’s control continuously since his or her most recent turn began. A creature can’t attack unless it has been under its controller’s control continuously since his or her most recent turn began. This rule is informally called the “summoning sickness” rule.
Also note the ruling on Gatherer, which explicitely answers your question:
Forests that enter the battlefield while Life and Limb is on the battlefield will enter the battlefield as creatures. They’ll have summoning sickness.
If so is there a reasonable to animate you're opponents land like this to set them back?
Not one that animates lands.
Animating lands is a weird effect, because it makes your lands combat relevant, but also vulnerable to interference. Any mass animation of your opponent's lands allows you to turn a mass creature destruction spell into a one-sided land destruction spell, and that's powerful. Really powerful. Which is not to say that it doesn't exist. Jolrael, Empress of Beasts will temporarily animate all the lands belonging to one player. But it's ridiculously expensive if all you want to do is give a single land creature summoning sickness (especially as it gives your opponent an army while you do it).
If you do want to slow down your opponent's land drops, I recommend one of the cards which force lands to enter the battlefield tapped. (+Orb of Dreams, which didn't fit in that list because it affects all permanents.)