They are getting much easier to find these days. Sally Hanson makes a line of nail art pens that you can find in any local grocery store or drug store.
I would go to Sally's since they carry that kind of stuff. You could also check amazon or ebay to see if they have any. You could also try froogle and see what comes up. You might also want to check a local drugstore and see if you can get lucky.
The best place to find any nail art is online. There are tons of sites that sell pens like you are looking for. However if you don't want to buy online you should check out your local beauty supply stores.
