Q: My mom who lives in Canada send me an iTunes gift and I can't open it. I live in the USA. Is there a way for me to redeem that gift?

No, all iTunes gifts and gift cards are country-specific - so a Canadian gift can only be redeemed in Canada onto a Canadian iTunes account.

I assume that it's an emailed gift ? She can try resending it to somebody else in Canada : http://support.apple.com/kb/HT1541

Or, and if she's been charged, she can try contacting iTunes Support and see if they will refund or credit her : http://www.apple.com/support/itunes/contact/ - click on Contact iTunes Store Support on the right-hand side of the page, then Purchases, Billing & Redemption