I’m at the Supernova Conference in San Francisco, where the coolest thing I’ve heard about is Pando’s new streaming P2P video service.

The company will allow publishers to offer their videos to be watched while being downloaded, which could be a real boon for encouraging long-form internet TV. Downloaders will have to have the Pando client, which has been installed 8.5 million times since it launched last year. The price is a head-turner; about half a cent a gig, Pando CEO Robert Levitan told me today.

(Update: Pando is actually offering a flat rate of $5,000 per million downloads of any size. So the half-cent price would be if your downloads averaged 1 gig. There I go trying to extrapolate and do math! Levitan said tonight that the pricing is going to be barely profitable for Pando, but it hopes to build interest before introducing higher-priced levels of services.)

Publishers will also receive online and offlines ad insertion, usage reporting, and an API for integration into their existing systems. Other P2P-CDN hybrids are out there from people like VeriSign, but not with the same kinds of publisher controls.

Blip.tv, Revver, and Next New Networks have signed on to offer the service to their publishers. Pando will not be offering a centralized index of content, said Levitan.

Update: Just spoke with AllPeers, who is also here with a P2P helper app. They showed me how their Firefox plug-in is going to incorporate BitTorrent starting July 10, so you’ll be able to download from torrents directly in your browser. The cool thing is the software is social, which quite naturally ties into the peer structure of BitTorrent, because when someone recommends a file to you they are probably also downloading — and uploading — it at the same time.