There are many resources which are available as hyperlinks which you can post into a course.  In order to respect copyright, materials which you find should be linked to instead of copied; when you are making a hyperlink to a webpage, you're referring students to where that material can be found, and therefore you're not making a copy, and therefore you're not infringing on copyright.  

Consider the following types of web sites as you search for resources.

• Textbook publisher web sites.
• Professional society and trades society web pages.
• Federal departments, bureaus, and administrations such as the National Institutes of Health, Federal Aviation Administration, Small Business Administration, National Science Foundation, Corporation for Public Broadcasting, National Endowment of the Arts, and OSHA.  Most materials developed for the Federal government are in the public domain since they've been paid for with Federal tax dollars.  Materials which are not in the public domain but are publicly accessible through web pages can be linked to from your course.
• Creative Commons materials.
• Open courseware materials released by other academic institutions, such as and materials released by other educational institutions (found through searches with the attribute  site:.edu). 
• Learning object repository such as MERLOT.org.
• Public broadcasting sites such as PBS.org, NPR.org, MPR.org, WPR.org, and the Annenberg Foundation's Learner.org.
• Sites which host a variety of podcasts and videos on different topics such as YouTube.com, TeacherTube.com, and OpenCulture.com.
• Commercial / corporate sites - under press relations / customer relations and technical support sections (tutorials, instructions, application and safety materials, etc.).