My iMessage is now working again! đ After speaking with 5 (no kidding) different people at AppleCare and 1 trip to the Apple store, they still could not fix the problem. Fortunately, each person shared some thought provoking information during our long conversations and I was able to combine that information to try a fix on my own. Here's the fix... Went into settings, messages, send & receive. My screen displayed my phone number first and my e-mail address second, but the phone number was not highlighted and there was no checkmark beside the phone number (just a dull gray color) and I could not "click" on it. However, I could "click" on my e-mail address so I clicked on it and deleted the e-mail address. I then shut the phone off. When I turned the phone back on I went to the same place and a checkmark was beside my telephone number! I then re-entered my email address and everything is working great!
On another note, I updated from IOS 4.3.5 to IOS 6.1.1 on an unlocked 3GS. I personally think it was just too much of a jump for my phone. I did have issues for a few days such as when I sent an SMS text my phone would say that the text failed (even though the person did receive the text) and sometimes the SMS texts did not go through even though my phone thought they did. However, these issues resolved themselves with 2-3 days. Don't know why, but they did.