Once you're married she will be eligible to get a derivative TD visa for the US, but she will not be able to work or do much of anything while she's here.
She can apply for the TD at the US consulate I believe, after you're married. She'll need to take a copy of your marriage certificate, and if you get married in Ontario, that can take a while apparently. I think they've sped it up some, but I've heard of couples waiting up to 6 months to get their marriage certificate in Ontario!
***edit in**
I deleted your other thread, you only need one as its all the same quesitons basically. I'll just paste the other questions:
1. Can she live with me in the US based on my
TN visa status?
2. Can she work in the US based on my
TN visa status?
3. Will she have to change her plates from CAN to US, driver's license etc?
4. She has a Bachelors Degree in Business. Does that fall under the TN occupations?
1. see my answer above.
2. No, she cannot work with a TD visa. She would have to get her own TN or other work eligible visa.
3. Yes, same as you do, depending on the laws of the state where you are living.
4. Check the sticky threads with specific into about TN job titles and whatnot regarding eligibility.