Daren,
It appears that Amazon is positioning itself to sue on the unconstitutionality of the internet tax if it is enacted in North Carolina.  At the very least they’re serious about not putting up with unfair taxation.  See this letter that was sent to participants in their associates program (where one can purchase books from Amazon through another?s website):

We are writing from the Amazon Associates Program to notify you that your Associates account has been closed as of June 26, 2009. This is a direct result of the unconstitutional tax collection scheme expected to be passed any day now by the North Carolina state legislature (the General Assembly) and signed by the governor. As a result, we will no longer pay any referral fees for customers referred to Amazon.com or Endless.com after June 26. We were forced to take this unfortunate action in anticipation of actual enactment because of uncertainties surrounding the legislation?s effective date.

Please be assured that all qualifying referral fees earned prior to June 26, 2009 will be processed and paid in full in accordance with our regular referral fee schedule. Based on your account closure date of June 26, 2009, any final payments will be paid by September 1, 2009.

In the event that North Carolina repeals this tax collection scheme, we would certainly be happy to re-open our Associates program to North Carolina residents.

The North Carolina General Assembly?s website is http://www.ncleg.net/, and additional information may be obtained from the Performance Marketing Alliance at http://www.performancemarketingalliance.com/.

We have enjoyed working with you and other North Carolina-based participants in the Amazon Associates Program, and wish you all the best in your future.

Best Regards,

The Amazon Associates Team

HT: MM