Recent advances in our understanding of the Universe have revolutionized our view of its structure, composition and evolution. However, these new ideas have not necessarily been used to improve the teaching of introductory astronomy students, much of which continues to use traditional textbooks with some supplementary videos or animation. This project goes beyond the traditional methods, using interactive tutorials and exercises that emphasize student involvement with data. In addition, we have conducted research into student understanding of fundamental cosmological ideas so as to develop effective web-based tools for teaching modern cosmology to introductory college students.