Here are a few of the recommended links to university rankings that we at AGF Tutoring use.
Seemingly the most referred to rankings so we all have to take notice.
QS Worldwide university rankings
The Times Higher Education rankings are some of the oldest and most respected. Their current rankings can be found here.
The Guardian offers a wealth of information regarding rankings of UK universities, ranking universities by specific subjects as well. Their rankings can be found here.
The Telegraph paper also has a respectable appraisal of the rankings of UK universities, by students themselves no less. Please find their assembly of rankings here.
The most reliable and most referred to source for US university rankings is the USNews whose rankings can be found here.