I do not want to advise you to get or not to get the H1N1 vaccine, but I want to give you some information. You and your medical provider should make the decision.
The H1N1 Flumist vaccine is an attenuated vaccine. This means that the virus is altered to prevent it from being virulent, but it still can replicate and lead to an immune response. Yes, there is always the chance for it to mutate, but this is not a very common thing.
The symptoms one receives when getting a vaccine are the body's normal response to a vaccination. It is very unlikely to get the disease from the vaccine. In most cases, the person ends up getting the disease from an outside source before the vaccine becomes effective.
I believe there is a lot of misinformation out there about the vaccines and I wanted to let you know what I know. Only people who have contact with transplant patients should not get the flumist (if they fall within the age range, are not pregnant and are not immunocompromised themselves).
Just an FYI - Two common child vaccines (chickenpox and MMR) are also attenuated vaccines.
I got the Flumist on Monday. I have not had any symptoms or issues. If you want more information, check out the CDC website.
http://www.cdc.gov/h1n1flu/general_info.htm
http://www.cdc.gov/FLU/about/qa/nasalspray.htm - Information about Flumist (not specifically H1N1 though)
Hope this helps. Its just the pharmacist in me. And I have been planning the vaccinations in my facility.