Low heat won't crisp the skin. Higher temperatures - around 400F - for pieces of chicken works. But then you sacrifice the tender, melting qualities if the "sticky" chicken. Also make sure that the skin is really dry before roasting and the pieces aren't crowded together in the pan.

To roast a whole chicken, this site explains it very well

http://www.taunton.com/finecooking/pages/c00015.asp

Karen