She has to get a specific TD visa in her passport, which requires an application to the local US consulate after your TN-1 is approved. You basically need to go to the POE, get your TN-1 and then she needs to apply for the visa. She needs proof of your TN-1 but that's basically a copy of your I-94 and proof that you're married (marriage certificate) in addition to the other paperwork for a visa, have a look at:
http://www.consular.canada.usembassy.gov/Bear in mind if you go to the US you will basically be in a position where you have to carry on filing as a resident of Canada and file as a non-resident of the US. For two reasons, firstly TN-1 requires "non-immigrant intent" which means you have to maintain residential ties to Canada. Some people ignore that and file as US residents anyway to save money, but in your situation your wife is an LPR of Canada and a claim of permanent residence in Canada is a residential tie. At least as far as the CRA is concerned.
Steve.