Here's the LDS Church's statement on how to assist:
SALT LAKE CITY |13 January 2010| The Church released the following statement this morning regarding the earthquake in Haiti:
We express our sympathy and prayers on behalf of the citizens of Haiti following the recent devastating earthquake. The Church of Jesus Christ of Latter-day Saints is immediately shipping humanitarian relief, including personal hygiene kits and supplies for newborns. Efforts are underway to determine further humanitarian response in coordination with government and disaster relief organizations. Donations for relief efforts can be made at http://give.lds.org/emergencyresponse.
All missionaries serving in the country are safe, and we continue efforts to account for Church members in the area.
The LDS Church does not charge for their services in disaster relief. 100% of your donation will go to the Haiti relief.