Free, online encyclopedias like the Stanford Encyclopedia of Philosophy and the Internet Encyclopedia of Philosophy contain entries on all sorts of topics in philosophy, broad and narrow -- all of which are written by professional philosophers. Peruse these encyclopedias to enhance your background knowledge of topics and major figures in philosophy as well as your understanding of intricate concepts you're learning about in your philosophy courses.
The PhilPapers Foundation provides free access to a number of useful resources in philosophy, including a comprehensive index of philosophy scholarship and an open-access repository where anyone can read and download full-text philosophy articles written by professional philosophers.
New to philosophy? Want to explore topics you haven't yet covered in your philosophy courses? Want to deepen your understanding of philosophical issues? Podcasts and short video lessons are useful resources for beginners and experts alike. For help with working through philosophical problems, Wireless Philosophy videos are designed to teach you how to do philosophy. And podcasts provide the listener with ample examples of how to engage charitably with others on philosophical issues about which there may be considerable divergence and disagreement.