Since there's not a strict standard regarding pork cut names, pork riblets could be button ribs (taken from the backk of the hog), sections of the brisket from the lower edge of a spare rib slab, or short sections of rib bones cut from either a baby back rib slab to make it less curved, or from a sparerib slab when it's cut to make KC or St. Louis style slabs. The last description is technically correct.
Depending on which type you have, cooking time, whether smoking or grilling, will vary. Season them just as you would spareribs or baby back ribs, but be cautious that you don't overseason them. Pieces with a lot of fat will shrink considerably, concentrating the seasoning/salty flavors.
The riblets will take a shorter time to cook that a whole slab, so they are great for appetizers to munch on as the rest of the meat is cooking.