That's really exciting kalenakai! Unfortunately, the initial screen is less extensive than the next phase, so there is a good chance that you may not actually match, but hopefully you will! It is so unlikely to get called, it is amazing that you were.
Bone marrow/Stem cell transplants are some of the most anticlimatic proceedures and simultaniously horrific experiences. If you have ever seen a transplant, it is so straight forward and simple and dull - it looks just like a blood transfusion, and the donor generally experiences very little pain or discomfort. But other than the transplant itself, they are a hellish experience for the patient, from high dose chemo and radiaton, to isolation and long term hospitalization, to graft verses host disease (rejection is the opposite than other transplants since it is the immune system being transplanted), and dangerous infections.
For the donor, they experience nothing remotely close to the receipient - in fact, their experience is similar to the "check-up" bone marrow biopsies reciepients get months and years after the transplant. it is extremely minor, and the outcome is potentially saving a life.
Just to address some things:
They're going to stick a pipe-sized needle into your hip!!
Yes, the needle is big relative to one for a blood draw, but you are either heavily sedated or under. It is done as an outpatient proceedure, and the pain afterwards is notthat bad, normally like a deep ache. Recovery is quick, most often getting over the anastetic is worse (someone I know who was a donor said getting her wisdom teeth out was a far worse recovery than donating).
like indo mentioned, there are 2 ways of donating: thru that long needle in your upper pelvic bone, and the other thru a blood filter/transfusion
The second method (pheripheral stem cell donation/transplant) is becoming increasingly popular. Like Tigress said, they do premedicate, and stem cells are collected similarly to platelets.
if you're in New York and there is a match in California, do you have to pay for the transportation yourself?
the marrow travels, not you.
Here is the website of the national marrow donor program:
http://www.marrow.org/