Opps, sorry.. guess it would have been good to actually answer the question.
Any private pilot can fly at night. There is a newer class of license called sport pilot that does impose restrictions on night flight (and quite a few other restrictions), but just about all pilots can fly at night.
I'm really confused by why people think it would not be ok to fly at night though. Just about everyone I've told that I'm a pilot asks about it though, so it's a big misconception somewhere. I always follow up with "Why do you think it wouldn't be ok?", but no-one's really been able to articulate why they thought that.
Flying at night without an instrument rating in some areas is pretty sketchy to be fair. More than one person has died by losing track of where the ground is and where it isn't. In much of Europe you actually do need an instrument rating to fly at night.
Because it's kind of like flying on instruments, which you need an instrument rating for? Because you are supposed to fly by visual reference to the horizon, which you can't see at night? I find it a bit weird myself.
