There are several websites for notes & summaries throughout.
I have found one of them, Shmoop, which I use side by side with my Audiobooks. We can't deny we listen as good as we read, even more so when listening to a complex work, i.e. Dante's works.
To compensate your reading I suggest using some cites which explain and give insights which we might not be aware of, specially since they were wrote in a different time and culture.
I will give Dante's works another go and have a better insight into his personage backgrounds and individual's deeds which cause Dante's mention and "placement" in his literature.
If anyone has a different/better source, please let me know, thanks.