You can download QST magazine (issues of 1998-2008) free.
Registration not required. Good quality. File format: pdf.
Other magazines on electronics, radio, computers and robotics can be downloaded from Free library here.
Free package of programs to work with pdf and djvu files can be downloaded here.
All free magazines that can be downloaded:
Amaterske Radio magazine 1952-2009 in Czech
Circuit Cellar magazine 1988-2013 in English
Electronique Pratique magazine 2006-2012 in French
Elektor Electronics magazine 1998-2014 in English
Evil Genius magazine 2004-2009 in English
Funkamateur magazine 1995-2013 in German
Nuts And Volts magazine 2004-2014 in English
QEX magazine 2005-2008 in English
QST magazine 1998-2008 in English
Radiotechnika Evkonyve magazine 1968-2008 in Hungarian
Servo magazine 2003-2014 in English
Stereophile magazine 2008-2014 in English
Радио Телевизия Електроника magazine 1973-2002 in Bulgarian
Russian, Ukrainian and Belarusian magazines can be found here.
Download archive of QST magazine free.