It appears that the migration of TV to the web has finally started, with the release of Joss Whedon's Dr. Horrible's Sing-Along Blog. This is probably the first online series to be produced by a big Hollywood name. (At lest its the only one I know of.) The series Stars Neil Patrick Harris, Felicia Day and Nathan Fillion.
According to the Movie Blog, when it released it, the site was brought down do to the amount of visitors to the site, and has since then managed to top the iTune's Downloads list. For anyone, interested in seeing this online just click on this link, or you can buy it in iTune's for $4.