Overnight Prints is a great option for rounded corner business
cards, available for just $2.00 per hundred cards. They also
have many shapes and card stocks to choose from. And great
prices to boot.
Moo.com offers rounded corner business cards like no other.
GORGEOUS templates, or design your own. If you've haven't experienced Moo's "multiple
designs, one pack" premise you've got to. Their thick silky card
stock is awesome.
PGPrint is super affordable and offers a lot of great rounding
options. Choose which corners as well as how whether you want
a 1/8" or a 1/4" corner. You'll find this as a drop-down menu
under "More Options." Sweet!