Have there been studies done or computer models of the possible effects on weather patterns of large wind farms such as T. Boone Pickens is creating?

I think a lot of people have dismissed your question outright as dumb, but in truth there is something to this that could be investigated.

There is a poster here, Tundrayeti, who firmly believes that we can power the planet on wind turbines. Studies have demonstrated that it's plausible, however it would take 14% at least of the earth's livable surface to do so.

Consider what kind of impact that would have on global weather patterns? Now this isn't a personal attack on Tundrayeti, but rather I used him as a segway into breaching this subject.

Wind power converts kinetic energy from the air into electricty, removing kinetic energy in the process. Would wind power not affect the high and low pressure cell distribution in the atmosphere? There are many questions that require investigation before we implement green solutions - because ultimately I think all sources of power generation are unfriendly to the enviroment.

use the hot air in dc you can heat the world

But the wind's there anyway. Turbines just utilise it, they don't create it so I don't really see how it could have a meteorological effect. As far as I know, there's no difference in wind power once it passes through a turbine. Maybe I'm wrong though...