One of my favorite websites is Biblical Training. This site includes audio lectures on a wide variety of biblical and theological topics from a broadly evangelical perspective. Much of the material is available for free.
The content of the lectures ranges from material suitable for new believers to seminary-level instruction. The lecturers include Bill Mounce, Bryan Chapell, Craig Blomberg, and Mark Strauss. Personally, I would not agree with all the theological positions found on this site, but I do think there is much that is worthwhile. A good place to begin is with the complete class list.