Can you put a Verizon sim card in an iPhone 3GS?

Verizon does have sim cards. if you buy a blackberry bold it will have a sim card made for Verizon, the bold was made to work with gsm and cdma and Verizon had a "hybrid" sim card made for that phone but i currently do not have a iphone but ive had friends who have put an iphone on Verizon before you might need to unlock it though