Our Lord traveled as an itinerant for only 3 years, didn't ask for donations, didn't drive a fancy car or have access to mass media, yet changed the thinking and beliefs of a good portion of the world.
Regardless of Osteen's motives though, the Lord is using him for His own purposes to reach specific people. Personally I choose not to listen to televangelists solely because I think fame and fortune have a way of turning the focus away from God, but I would never support a movement to silence these preachers.
Again, regardless of satan's involvement, the Lord can turn any situation to good use. Some, like myself, trust the person who has been through the fire, others view things differently, so you are correct. It does take all kinds.
Certainly many of the TV preachers fall prey to the money and power that comes with these mega-ministries. Jimmy Swaggart and Jim Bakker are two prime examples. And as many millions that can turn to Jesus, they can turn 10 times more away when they fall. It is good that they can reach around the globe, but the millions of dollars that follow leads to temptation. Too many folks are quick to condemn all TV preachers. Seems like the biggest complaint against Osteen teaching is he is just too darn positive. They have a point, there needs to be a balanced message, but that is no reason to condemn him.