I'm really not sure where I stand on this, but this guy makes some good points, and has videos/pictures to back them up.

http://www.weatherwars.info

Read. Alot. Especially about the chemtrails.
I have seen these alledged "chemtrails" and just this morning I saw a cloud that was a perfect parrelelogram(sp?) cloud; it was spectacular. This stuff is hard to swallow, but it makes sense considering the not-old people(me included) under around 30-40 years old have been seeing this since birth, so these odd cloud formations/chemtrails wouldn't seem odd.
Let me know what you guys think, and please correct me if my information is inaccurate.

Edit: Even if you dont read all the stuff, make sure you look at I "A pilots view". Some really amazing photography there. Very convincing.