CRA’s document “Gifts and Income Tax” (P113(E) Rev. 09) is helpful for Canadian charities and taxpayers understanding what is a “gift” that can be receipted.  The document is located at http://www.cra-arc.gc.ca/E/pub/tg/p113/p113-e.html Here is an excerpt dealing with carrying forward tax credits.

“Carrying forward tax credits
You do not have to claim, on your return for the current year, the eligible amount of gifts you made in the year. It may be more beneficial for you to carry them forward and claim them on your return for any of the next five years. No matter what your choice is, you can claim them only once.
You have to claim tax credits for gifts you carried forward from a previous year before you claim tax credits for gifts you give in the current year. If you are claiming a carryforward, attach a note to your return indicating the year of the return with which you submitted the receipt, the portion of the eligible amount you are claiming this year, and the amount you are carrying forward.
Usually, you can claim gifts on the return you receive. However, you have to use a T1 General Income Tax and Benefit Return if you are claiming:
• gifts to Canada, a province, or a territory agreed to in writing before February 19, 1997;
• gifts of certified cultural property;
• gifts of ecologically sensitive land; or
• most gifts in kind (see “Gifts in kind” for details).”