Hopefully, you've already read Bunyan's Pilgrim's Progress. If not, I sincerely suggest you get off the Internet, go find a copy, and read it. Not an abridged version - the full thing. Once you have developed an appetite for his writings, read Christiana's Journey as well, which is often bound together with it, and finally The Holy War.
But there are other good writings of Bunyan, as well as a few that are sub-par: after all, he was not an educated man, but simply a tinker with a Bible and time on his hands, thanks to religious persecution that forced him into jail. The following discussion of his regarding sanctification is well worth reading and taking to heart.
(link to Bunyan on Sanctification)
He is a simple man, with a simple message, let us all try to follow it:
Depart from Iniquity!