Well like a lot of other phone the Blackberry Pearl uses a micro sd style storage card. They can be purchase from a lot of place. Be sure to check the maximum capacity that your phone can use so you don't but one that is too big.
Depending on your phone compay, you may not need a sim card at all. Remember the sim card generally comes with the phone. For example if you have a T-mobile blackberry, you will need a T-Mobile sim card.