Haitians need help in the most dire way. Along with governments, private charities are springing into action. The quickest and easiest way for the average person to help is to give money to those charities. Many charities are accepting donations that will be specifically directed to Haiti.
CanadianCapitalist has posted one list today with links to a few charities. He also references this bigger list on the CBC website, which unusually for the CBC, actually includes direct links to the charities' websites to make donations. The CanadaHelps.org charity portal conveniently provides an extensive list of charities that are accepting Haiti-specific donations and a capability to make a donation on-line to any one of them (it does deduct a 3% fee from donations through its portal - which I think is reasonable as I discussed here).
Charities will differ, often substantially, in their effectiveness and efficiency in transforming our dollars to into help for victims. Some charities will help Haitians a lot more than others even when their mission sounds great. The best available source for hard information to assess this factor I've found so far is the Canada Revenue Agency Giving to Charity page which includes mandatory accounting returns from every registered charity in Canada. Find the Charity Information Return (the T3010) using the Search for a Charity tool.