Jeremiah airs on Showtime here in the States. It's in an odd sort of limbo now - JMS (who wrote Babylon 5) wrote both the first and second seasons. However, Jeremiah's future looks grim - they only aired half the second season here (though the other half was aired elsewhere). JMS had a large fight with MGM (Showtime's parent company) because they were pushing for him to make changes they thought would increase ratings. JMS is notoriously unwilling to compromise with netowrk executives, for better and worse, and he left the show. It's unknown if the second half of the second season will air on Showtime, or if the show will be renewed.
Jeremiah is the story of two people in a post-apocalyptic society in which a virus killed every person above the age of adolescence. The show takes place fifteen years after this event (The Big Death) in what was once the United States, where the show's title character, Jeremiah (Luke Perry) runs into Kurdy (Malcolm Jamal-Warner) and eventually the pair end up at a place called "The End of the World", also known as Thunder Mountain. The first season explores Jeremiah and Kurdy's friendship, past, and the origins of the Big Death. The second season continues with Jeremiah, Kurdy, and Thunder Mountain struggling to create their dream of a coalition of groups.
The show is based off of a graphic novel of the same name by an author I can't recall the name of, though his name is in the title credits. I'm not sure how closely it follows the source material other than the premise of the Big Death, but you could gie that a read as well.