Lots of ways here or Disasters Emergency Committee Haiti Earthquake Appeal or more grassroots efforts- Partners in Health or Haiti Emergency Relief Fund or Papaye Peasant Movement (MPP).
Also demand your govts stop deportations of Haitians and release them from migrant jails, in the US case grant Temporary Protected Status, Homeland Security Secretary Janet Napolitano temporarily halted deportations but that is all so far (ht2 Nezua).
Update: Temporary Protected Status has now been granted.
Ten Percent 