Many women take kallah classes before getting married in order to be familiar and comfortable with the laws of taharas mishpacha. I have heard that there are similar classes for men, and it makes sense to me that the man should be comfortable with the laws as well. When I search online for information about such classes, though, I find very little information. What exactly would be covered in a chasan class, and how might one find such a class in his region?
Yes, such classes exist, and are recommended for potential bridegrooms. Speak to the rabbi of any orthodox synagogue, and he should be able to direct you someone who can tutor you in this field. So, I suspect, can the head or mashgiach of any bes midrash. Covered topics are hilchos nida and v'sasos, k'vod ishto, and others, though the exact list varies from tutor to tutor.
These classes are usually one-on-one chevrutot with your rabbi (or someone he directs you to), so you're not going to find them online, or even with a fixed schedule.
Talk to your rabbi and he will direct you what to do.