Ok, you would have to go down to your city hall (double check with your town) and ask for a sellers permit. If you plan on doing business with another name besides your own name, you need a DBA, or Doing Business As. I think the DBA is first, then you get the Resale Number, but for us it was all at city hall, just different offices. Your Tax Id number should be your social security number if you are the sole proprietor, which it sounds like you are. If you have a partner, then you need to do other stuff and then get a tax id number thats not one of your personal ssn.
Ahhh, I remember starting up. Its been 10 years! Geez. How time flies. One word of advice. Do your flippin taxes! Don't let it pile up like I did. UGH.