we make meatballs (for tomato sauce and pasta) out of ground turkey fairly often, and they always come out good. i've brought some into work and even a few of the mama-lovin' italian guys couldn't immediately tell that they weren't the standard beef/pork/veal mix. one guy had first guessed they were just made of more veal than the other two meats.
for a pound + of ground gobbler, add 2 jumbo or 3 large egg whites (the yolks make it too heavy), about a cup and a half to 2 cups of seasoned breadcrumbs, a cup and a half of freshly grated locatelli (or 2 cups grated parmesan) cheese, 2 cups of dried parsley, a tbsp of dried oregano, and a half cup of milk.
mix together by hand until incorporated, and adjust so that it's sticky but not too gooey by adding more breadcrumbs if too wet, or more milk if too dry. it should stick to your fingers and the bowl a bit, but not be difficult to roll into balls because it's too loose.
scoop out enough to roll into balls larger than golf balls but smaller than baseballs. brown on all sides in evoo over medium heat, then plop into a crockpot of waiting bubbling sauce, set on high. let simmer for an hour or so.
they're ready to eat after an hour, but are better the next day after they've had time to breathe in the sauce.