Canadian Military just landed there with a C-17 transport and brought a Bell 412 with them. Americans will certainly bring Blackhawks - every time I went there before they would occupy the west end of the ramp with 5-6 Blackhawks. The UN mission used to have Bell 212's and 205 from some of the South American contingents - don't know if they had anything there before the quake.
Driving through Port-au-Prince before it always looked like it had just gone through an earthquake, I can't imagine what it looks like now. The better hotels and businesses already had their own generators and water was trucked in and around or caught in cisterns, so in some ways they would be semi-prepared.