Biden's campaign just sent out this release, probably because they're sick of getting asked about it:
"There are no discussions underway and there will be no deal with any campaign. We believe Sen. Biden is strong enough on his own. Everyone knows that Sen. Biden is a popular second choice for the supporters of all the other campaigns. We remain confident that Sen. Biden will surprise folks this evening."
The funny thing is, the statement suggests that Biden isn't making any deals in which he would take supporters from non-viable candidates. When in reality, seeing as he polls in the single digits, any deals he makes would more likely be with a frontrunner like Clinton or Obama, in which he would throw his supporters their way. He should be more worried about losing his supporters to a leading candidate than drawing supporters from non-viable candidates like Dodd, Kucinich, and Gravel.