The IMF is an agency of the United Nations.
The IMF is not a bad thing, seeking to squeeze repayment from countries like Haiti who could never repay anyway.
The IMF has just approved $102 million in aid to Haiti. Although this must be shown as a loan (the IMF lends money) one should not be afraid that Haiti will have to use your donations to pay back the IMF. Haiti doesn't pay it's debts. No need to fret.
Additional information added from Reuters newswire, 1/28/10:
Some $1.2 billion of Haiti's debts to the IMF and World Bank were written off in July last year as a reward by the international community for progress the country was making in economic reforms and management.