Bhikkhu Thanissaro is doing an amazing public service that deserves more recognition and gratitude. On his site, dhammatalks.org, he has made a significant portion of the Sutta Pitaka, the ancient Buddhist scriptures, available—free of charge—in a series of compilations. Included with these compilations are an assortment of helpful essays, treatises, and study guides.
His renderings of the verses from the Samyutta Nikaya and Sutta Nipata are particularly refreshing, and provide clarity to the commercially available translations that are sometimes more cryptic due to their more literal translation.
I recommend starting with The Buddha’s Teachings: An Introduction, which provides a brief introduction to Buddhist practice, and then reading The Wings to Awakening to get a feel for the teachings in more detail. If you’re just interested in mindfulness and meditation, try the treatise With Each & Every Breath: A Guide to Meditation.
dhammatalks.org also has a podcast that you can subscribe to via rss feed or YouTube.