Rapper Petey Pablo -- Sneaks Into Prison

Bad News: Rapper Petey Pablo kicked off his 2012 by reporting to prison.
Good News: At least he's going to get an education out of it.

The former platinum selling rapper -- who was arrested for trying to smuggle a gun through an airport ... on SEPTEMBER 11 of all days -- finally began his three-year prison term on January 4 by turning himself in to a medium security federal correction institution in West Virginia.

According to court docs obtained by TMZ, the court recommended Pablo receive "intensive substance abuse treatment, vocational training and educational opportunities" while locked up.

He is scheduled be released on July 17, 2014.