It looks like iMessage is experiencing some issues at the moment, reports The Next Web. They're also seeing reports on Twitter with many, many angry customers posting messages every few minutes. The issues look like they're hitting all sorts of iOS users.
But, iMessages coming from Apple IDs and on Wi-Fi are experiencing less issues than those on cellular networks, but there are still hiccups. The past 24 hours have seen problems with iMessage, with complaints mounting up since 10:30 AM PST.
It shouldn't affect iPhone users too much, as they can fall back on text messages, but iPad and iPod users are left in the dark without iMessage. Right now there seems like there's nothing you can do, and there should hopefully be a fix soon from Apple.