The current default rule throughout the United States is that you must collect sales tax on Internet sales to customers in those states where your business has a “physical presence.” The physical-presence rule is based on a 1992 United States Supreme Court decision, Quill Corp. v. North Dakota, that addressed the obligations of mail-order businesses to collect sales tax on out-of-state sales; the decision has been extended to include online retailers. Generally speaking, a physical presence means such things as:having a warehouse in the statehaving a store in the statehaving an office in the state, orhaving a sales representative in the state.
J.K.Logic Wrote: Looks like they are still in the works of working through the finer details nationwide, and its really not clear at all if they are close to a national answer. Seems like its a state by state solution. As this is not quite complete enough an answer, please share if you find a better one.