Besides the occasional lectures offered online by the seminaries themselves, there is a treasure trove of seminary class lectures available online.
Dr. William Weinrich, early church scholar extraordinaire has five different classes available online, including the must-hear Early church. The classes are available HERE. After I did the original digital transfer, Pr. Lange edited the Early and Medieval church files. You can listen to those at his site HERE. (Pr. Lange has other lectures as well.)
Newly added online is a collection of the works of Dr. Kleinig of Luther Seminary in Adelaide, Australia. Available classes include his lectures on Spirituality and Introduction to the Bible. Also available are his classic lectures on Leviticus. Check out the site HERE.
If only someone would add the lectures of Dr. David Scaer. I know that several people have recorded his lectures throughout the years. Sadly, I was not one of them. Hopefully those will be transferred and made available someday. I think the church would benefit greatly.
If you recorded, or know of someone who recorded seminary classes, encourage them to make them available (With the permission of the professor, of course.) The more good theology we can listen to and share, the better the church will understand her own task in proclaiming Christ crucified.