Have you checked out the Beginner's Guide yet? It's a very helpful resource, as are the Internet, print books like The Cherrypicker's Guide, and old posts on this forum.
Copper pennies (all pre-82 except 43 steelies, and about 3/4 of 82s) weigh in at 3.11 grams and Zincolns (all post-82 and approximately 1/4 of 82s) tend to be around 2.5 grams