Curious. For all you iPhone owners. From the time some one sends you a message how long does it take for your to receive?

I don't have an iPhone yet. Waiting for the iPhone 5. I do have an old Samsung flip-phone I'm borrowing.

My real estate agent sent me a message this morning at around 9:40 AM. I didn't receive notification on my cell phone till almost 2 PM. Is it my provider or the cell phone? Ideas?