Anytime you are collecting data for research and them reusing it for some type of publication, even homework, you should always cite your sources.  This not only gives the author of the original work credit, but it also gives your reader access to find out more information on the topic if they want to pursue your thoughts.

If you are performing research on the Internet, you will need to keep track of where and when you found the information.  A bookmark of the link with definitely help, but keep in mind, you will also need to know the date in which you gathered the information.

Resources

Here are some resources to help you in creating bibliography records for your sources:

Citing Sources and Avoiding Plagiarism: Documentation Guidelines, Guide to Library Research link: http://www.lib.duke.edu/libguide/cite/works_cited.htm

NoodleTools Quick Cite! Link: http://www.noodletools.com/quickcite/ - Use this site to create your bibliography records.