Fallon, who was a regular on 'Saturday Night Live' and has appeared in films including 'Almost Famous', 'Band of Brothers' and 'Factory Girl', has been named as the replacement for Conan O'Brien who takes over the 'Tonight' show from Jay Leno next year.
Lorne Michaels, executive producer of NBC's 'Saturday Night Live', said that he wants Fallon to iron out as many rough spots in his presentation as possible in performances on a website.
Michaels said that his experience launching 'Late Night with Conan O'Brien', who took over from David Letterman, had taught him how hard it can be to launch a new late-night host.
It is not known yet which website the shows will be posted on but they are expected to begin in the autumn, well before Fallon takes over from O'Brien.
Michaels added that the internet would give Fallon more freedom in terms of what he can say and do and "more opportunity for experimentation".
Other shows to debut on the internet include ITV's teen drama 'Gossip Girl', which appeared on its website before it aired on ITV2. The broadcaster also signed celebrity blogger Prez Hilton to write a weekly column to support the show.
Earlier this month Google teamed up with 'Family Guy' creator Seth McFarlane to distribute a series of 50 two-minute animated clips, called 'Seth MacFarlane's Cavalcade of Cartoon Comedy'.
The clips will be presented online through Google's AdSense network, which can syndicate video content to advertising slots on thousands of websites targeted to reach specific demographics.