I think some oil companies (like BP) are paying lip service to the alternative energy types with their stupid, condescending ads, but I doubt if they are sincere. Anyway I hope not.
It's more than lip service. The major manufacturer of solar cells is an oil company. The oil corporations will be right there as we convert to other, more expensive energy.
I guarantee you they are sincere. However, they also realize how far down the road it is. You can't sell technology that does not yet exist.
One interesting fact is that the chemical industry is also being touched by this. It's not just energy. How do you produce all the chemicals that we need without oil?
It turns out that there is a big push in the chemical industry right now to build what they call the "biomass refinery." They are going to try to produce chemicals from biomass. DuPont is one of the leaders in this effort.
It's not as far fetched as it might seem. With genetics, etc., becoming a more doable thing, there are a lot of opportunities to advance this technology that were previously not available.
But it's still decades off, so here's hoping that the oil doesn't run out too fast. The Russians and Iranians have a lot more oil than we have. He who has the last billion barrels of oil will rule the world.