For those who haven't been reading the Manga, you can get the English translations here.
Essentially, it's a Japanese take on the Zombie Genre. It's about several students from a Japanese High school (And the school Nurse, but she's an idiot) that get caught up in the zombie apocalypse and their attempts to survive while they are trying to meet up with their families. It can be humorous at times and there is often a lot of cheesecake, but it's actually pretty bleak, especially once they start meeting other survivors. It's a pretty good read, and it does bring up some issues that you might not consider about the situation, like the elderly woman who needs periodic transfusions just to live. Its got nothing on The Walking Dead, but I highly recommend it.