This is happening all over, state by state. They just did a compromise deal in California which delayed it for a year but when it's done they will collect sales tax there too. NJ is also pushing to start charging sales tax for Amazon. Etc.
Also, I don't know if you guys in Texas are aware of this but I have never been charged tax if I buy thru a 3rd party vendor on Amazon. I even bought from Pauls via Amazon and was never charged sales tax.