If you are referring to deleting your emails through the native app, you will not be able to do a mass delete. You can only delete one at a time by sliding your finger from left to right on each email. A delete button will appear to do this.
In order to do a "select all" you will need to go to your email server to do this function.
I want iPad 2 but 3 is coming I believe so I may wait.
I want to use it on the move so what do I need to buy, I have Internet at home but want to take it out and use it anywhere, is it extra monthly payments !