Apple’s iOS 5 feature called iMessage is a bit broken. The request either times out or is unavailable at this time. These messages are blue instead of the typical green.
I purchased an iPhone 4S earlier this year. I was excited for many of the features, but mostly excited to be able to iMessage my friends. iMessage was supposed to sync across my Mac and my iPhone, which is really cool, but I have yet to be able to sync all of my iMessages from my phone to my Mac.
I also remember that a lot of iPhone users were really looking forward to the new feature because they would be able to cut down on their use of SMS messages.
The issue seems to be that when you have an iPhone, iOS defaults to your phone number as the caller ID to sync to, and an iPod or iPad cannot be mapped to sync those messages between all of the devices.
Logging on with your mac.me address would hopefully fix the problem, but that is not the case. There are still a lot of bugs.
Hopefully Apple can fix some of these problems in an upcoming update.