• http://economia-publica.uab.es/ (Spanish)

contains an useful section to evaluate your level coping with Cost-Benefits analysis problems

• http://econpapers.repec.org/ (English)

you can find a wide variety of Articles, Papers and Books to download

• http://www.adb.org/Documents/Guidelines/Eco_Analysis/glossary.asp (English)

essencial economics concepts

• http://www.econlib.org (English)

another great source for books and papers where you may find authors such as Smith, Ricardo or Keynes.