Junit3123 is reporting that on ESPN's Draft Preview Rick Bucher confirmed a promise made by the Blazers to the Oden camp that Portland would take Oden #1. From Junit:
Bucher said Oden's camp has recieved a promise from the Blazers that he will be the #1 pick, the players loved him, the team loves his talent, and they were swayed by his personality.
Promises like this are quite frequent and usually true. That's not to say ESPN has never been wrong before but this puts a lot of weight on the Oden side.
Update: The plot thickens! Courtesy of Jason Quick: Read rebuttal here. (And now KP has weighed in too.)
Update: ESPN sticking to their guns here.