So I did a little searching and found some charts.
Here's one from Treasure Valley Sheep Producers. It looks like it's a scanned in copy from the National Live Stock and Meat Board. (Who knew there was a National Live Stock and Meat Board? Not me.)
(You can click on it to have it bigger.)If that's a little too "butchery-y," check out this link over to American Lamb's "Lamb 101 - Cuts" page. It breaks it down a little more basically, and has photographs of some of the different cuts.
And if you want to start from the "ok, it's called THIS; now, what does that mean?" side of things, here's a page at The Nibble that's a glossary of lamb terms.
Ok, my question's answered & I hope you've had a chance to learn something new, too!