very very small increase in speed.
Not Actually, if its a Cortex A9 its quite a bit faster even tho its only 200 MHz faster clock you will notice a decent overall performance increase. If its a Dual Core A9 then you will really notice a difference in overall performance.
It depends to on how much ram they put in the iPad 2 as well. A dual Core A9 with 1 GB of ram will be a really fast iPad.