In this video, John MacArthur shows how the teaching of Joel Osteen is really satanic. Osteen's message is that we can have it all now - your best life now. As MacArther indicates, that would only be true if one were going to hell.
If one looks at Osteen's "church", it is actually a converted sporting arena that holds over 16,000 at one time. Is this a sign of truth? I think not. When Jesus preached the truth, he actually lost disciples. If you only preach what the people want to hear, they will come. Hitler knew this. He led people by talking about their basest, ugliest desires. Osteen's message is a little prettier, but no more Godly.