RIM has opened their official Blackberry accessories store called ShopBlackberry.com, where you can purchase cases, charges, travel packs, and much more. The majority of the products they list are currently OEM that was already prepackaged with your Blackberry. You can order the original holsters, chargers, and batteries incase you ever misplace them. They do sell additional products that do not come originally with your Blackberry like a travel pack, leather pouch and sport cases, and high capacity battery that you may find useful. For an official store prices seem to be really affordable, leather cases start at only $26.99.
Visit the store at ShopBlackberry.com