There are plenty of dodgy resources and websites out there (known as Essay Mills) that may appear legitimate at first, but are nothing more than pirates offering to plagiarise your essay for you and take your money for their trouble .  

Here is a list of ethical sites that may assist you in your studies:

Enhanced Learning Educational Services (ELES) 

Fantastic study skills resources & study skills sessions for secondary schools.
http://www.enhanced-learning.net

Academic Tips

Tips and tricks to help you plan your time, study, and handle stress.
http://www.academictips.org

University of North Dakota

Student Success Centre is easy to navigate and has a number of excellent study resources.
http://sas.und.edu/learningservices/skillsaids.html

Prentice Hall Student Success

Tonnes of interactive information to help you study
http://www.prenhall.com/success/index.html

Plagiarism dot org

This is a really useful and comprehensive collection of articles and information on plagiarism.
http://www.plagiarism.org