As the fall TV season approaches, most broadcasters are hoping to lure viewers by heavily promoting downloads of the new shows. The Hollywood Reporter surveys the offerings, finding that NBC is betting most aggressively that showing pilot episodes will ultimately draw viewers to primetime, while ABC devoting its promotions away from the web, finding that such moves will only detract from the premieres. CBS is trying to maintain some secrecy of its online initiatives. So at least initially, extent of the online fall preview includes:

—NBC: The network became convinced of the value of online previews to draw a TV audience last year, when 350,000 people streamed the first episode of the sci-fi hit Heroes on Yahoo. So, starting September 10, Amazon.com will make NBC’s new dramas, including Chuck, Life and Journeyman, available on Amazon.com. Secondly, Facebook’s Apple 4 million member student group will be able to exclusively download the three NBC shows via iTunes. A week later, the iTunes downloads will be released to all.

— Fox: Last week, Fox began streaming the premiere episode of the new crime drama K-Ville as well as the first 17 minutes of the returning Prison Break across 200 sites, including Fox.com, AOL.com, Yahoo, TVGuide.com and IGN.com.

—CBS: Although it’s keeping mum on what sort of previews it might offer to web users, much of CBS’s plans revolve around ancillary content The network is producing music videos and video mashups of the CSI franchise. The videos are an example of the type of content CBS is distributing on its Interactive Audience Network.

—ABC: While abstaining from the online premiere bandwagon, ABC is being forced to try something out of the ordinary. The is playing the contrarian by showing previews at live events around the country. ABC is hosting small town versions of old Hollywood style premieres, in hopes of generating excitement for its new programming. “We don’t release full episodes before they premiere on the network unless it’s in a big social setting,” Michael Benson, EVP, marketing at ABC Entertainment, tells THR. “It’s just something we don’t believe in.”