It would seem that NBC is going out of their way by pretending that Conan O'Brien never existed. Just a few days ago Hulu.com had available every recording of the Tonight Show with Conan O'Brien. Now as of today, none of them are to be found. Same thing for NBC.com and YouTube.
The only logical conclusion for this must be with the The Tonight Show being back on the air with Jay Leno.
Interestingly enough, Sarah Palin was the first guest since Jay Leno came back and one of the things Leno said was that Palin has never been on a late night show (which is false) as Conan O'Brien had her on as a guest. This seems to insinuate the notion that Conan O'Brien never existed on NBC before...
If it's true that this is what NBC is trying to accomplish, then that's pretty shitty considering that Conan worked for them 17+ years.