Hikari,
You can find salted cod and pollack (close first cousin of cod) roe at the larger Korean stores i.e. Chicago Food Corp. and Arirang. My family used to eat it quite a bit growing up usually in a jigae or spicy soup or just sliced and served uncooked as part of our panchan. Uncooked, it presents an interesting taste and texture, though you have to be a bit of a salt-aholic. In case you don't have them, here are the addresses for both stores:
Arirang Super Market
4017 W. Lawrence Ave, Chicago
773-777-2400
9:30am-9pm Mon-Sat, til 7pm Sun
Chicago Food Corp.
3333 N. Kimball Ave, Chicago
773-478-5566
7am-9pm Mon-Sat, til 8pm Sun
Also, fwiw while looking up the address/phone number for both I came across this webpage which has quite a few city and suburban Korean stores location/contact information conveniently located on one site.
http://chicagoseoul.tripod.com/food.htm
John