An excellent database of taxes in the European Union countries:
The Taxes in Europe database is the European Commission's on-line information tool covering the main taxes in force in the EU Member States. Access is free for all users. The system contains information on around 500 taxes, as provided to the European Commission by the national authorities. The information can be found quickly and easily using the search tool.
The Taxes in Europe database contains, for each individual tax, information on its legal basis, assessment base, main exemptions, applicable rate(s), economic and statistical classification, as well as the revenue generated by it. The information is listed in the form of a downloadable file.
More information here. I only had a quick look, but so far I am impressed. The database is comprehensive, information is displayed clearly and the search function works well too.