ipads come carrier unlockd, they should work with any GSM carrier that allows it.
Yes ipads are all unlocked.
no they dont take normal simcards. they take Micro simcards, you can however cut a normal simcard down to micro simcard size.
no you cant use a Verizon simcard. there is no such thing, Verizon is a CDMA carrier and only GSM carriers have SimCards.
in the US you can put a t-mobile simcard in the ipad and it will work, however the ipad would only word with t-Mobile Edge and not 3G.