CNBC says that according to the usual "person familiar with the matter," Sprint has locked up the Pre and thrown away the key in the US through at least the end of this year. Granted, if the Pre doesn't come out till June, which is looking likely, that's only about a six-month window of exclusivity, which is still much shorter than say, the iPhone, which is going on two years at this point.
Since the Pre is what's gonna save Palm (if it can), you can bet they're itching to put it on as many as carriers to make it available to as many people as possible to kickstart their new platform. Also, don't forget that the Pre is just the first of many WebOS phones, so there'll be plenty of other hardware running the multi-tasking wunderkind OS. [CNBC]