I'd be very wary of anyone offering to hold your Dinar for you....There were a couple of these type deals being offered by sellers on Ebay.
Iraqi Dinars are not covered by FDIC insurance like your U.S. dollars are. You may find that if you set up one of these intrest-bearing Dinars accounts and go to withdraw your "funds" that they don't exist...
Personally, I'll be keeping my Dinars in my safe and let them earn their own returns as they have been doing steadily since the NID were issued.