SOME INTERESTING READINGS ABOUT TAXING THE E-COMMERCE
Directive 1999/93/EC of the European Parliament and of the Council of 13 December 1999 on a Community framework for electronic signatures
Directive 2000/31/EC of the European Parliament and of the    Council of 8 June 2000 on certain legal aspects of information society services, in particular e-commerce in the internal market (Directive on Electronic Commerce).
Report to Congress. Advisory Commission on Electronic Commerce April 2000. USA
The Internet Tax Freedom Act (formerly known as S.442, now Title XI of P.L. 105-277, the Omnibus Appropriations Act of 1998). USA
Report of the Commission for the analysis of the impact of Electronic Commerce on the Spanish Tax Sistem. SPAIN. http://www.minhac.es/comfisc/inicio.htm         
Ministerio de Hacienda / Ministry of Finance. SPAIN