This just in from Dr. Horrible's lab: By popular demand, and a hell of a response from the crowd at Comic- Con, "Dr. Horrible's Sing-Along Blog" will be offered via web streaming on Hulu for the next four months.

It's a slight departure from the Dr. Horrible world domination plan articulated by mastermind Joss Whedon a few weeks ago. When the first installment of the Internet musical monster was unleashed July 15, the notion was that it would only be available for free for a six days via the www.drhorrible.com site, and then taken down to build demand for a DVD release. (A guestimate on the traffic numbers for its July 15-20 stint is about 1 million views.)

But an extended engagement on Hulu seemed in keeping with the D.I.Y spirit of the supervillain tuner, which Whedon funded out of his pocket just to see what he and his brothers Zack and Jed and Jed's fiance, Maurissa Tancharoen, would come up with if left to their own devices. With the help of stars Neil Patrick Harris, Nathan Fillion and Felicia Day.

"Dr. Horrible" will remain available on iTunes as a paid download, for those who just have to own it. Meanwhile, Joss' reps are taking meetings with homevid distribs who want a piece of the DVD action, which Joss has promised will include a second musical dubbed "Commentary!," as well as a proper (well...) commentary track.

To herald the Hulu deal, Joss posted a blog entry on Hulu.com calling the NBC Universal-News Corp. joint Internet vid venture "the premier site for people who like joy and life and children and America."

How to describe "Dr. Horrible's Sing-Along Blog?" High-quality superhero-and-supervillain fun. With a swell soundtrack of original tunes.

The first thing I noticed about the Internet musical created by the brothers Whedon -- Joss, Jed and Zack and Jed's fiance, Maurissa Tancharoen -- was how fabulous it looks. No YouTube grainy-blurry here, thanks to the talents of director Joss and d.p. Ryan Green.

The second thing I noticed about the production was ... nothing because a few minutes in to Thursday night's screening of the 40-minute program at CAA, I was thoroughly engrossed. Gotta hand it to Joss and Jed for their skill in penning the tunes, which really make "Dr. Horrible" work as a tuner.

Not gonna spill any story details, at the request of the creators, other than to say it's cheeky and comic book-y with a love story at the center. It is, of course, elevated by the strength of its cast. Neil Patrick Harris and Nathan Fillion are fantastic; it wouldn't work if they weren't as good as they are in their roles. Felicia Day is just right as the unconventional love interest; sidekick Simon Helberg is equal parts perspiration and inspiration.

"Dr. Horrible" is a Joss-led attempt to test-drive the made-for-Internet production business, on his own dime (more like low six-figures though no one would get specific on the budget) and with a lot of help from industry friends. It was, as might be expected, very liberating and tons of fun, Harris opined in a post-screening chat with reporters and bloggers.

"We had the freedom to be like professional amateurs," Harris said, and that sensibility was "worked into the vibe of the film."

It's always nice when a pleasant surprise pops up in your inbox late in the afternoon. That was the case with an invite that came out of the blue for a screening next Thursday (July 10) at CAA of Joss Whedon's latest concoction, the made-for-Internet "Dr. Horrible's Sing-Along Blog."

It's a three-parter with name-brand stars, Neil Patrick Harris, Nathan Fillion, Felicia Day and the fabulous Simon Helberg from my new favorite show, "The Big Bang Theory." "Dr. Horrible" seems to be something of a Whedon family hootenanny. It's penned by Joss, his brothers Jed and Zack, and Jed's fiance, Maurissa Tancharoen. Jed and Maurissa are writing partners working for Joss on his day job, the upcoming Fox drama "Dollhouse."

Zack, as readers of On the Air already know, is a comer who is not only endowed with screenwriting in his DNA (his father and grandfather were also in the family biz) but was taken under wing a few years ago by none other than David Milch. Zack (pictured right) worked with Milch on "Deadwood" and "John from Cincinnati," and even wrote "John's" big-wave-wild finale (I'm not ashamed to say that I really enjoyed that show).

In his spare time during the past few months, Zack's been busy working on "Dr. Horrible" and writing a comic book, "Captain Hammer," based on a character from "Dr. Horrible." You can check out his comicbook wordsmithing right here.

"Dr. Horrible," which Joss also helmed, is set to be unleashed on the Web over three days -- July 15, July 17 and July 19. If there's some numerology significance to those dates, maybe we'll find out about it at the screening.

On the "Dr. Horrible" website, Joss explains his reasoning (as only he can) for tackling this project.

"JOHN FROM CINCINNATI" SPOILER ALERT, PART TWO:

Among the many interesting things about the "John from Cincinnati" finale seg is that it heralds the ascent, in WGA terms, of Zack Whedon.

Zack is the latest addition to the Whedon clan's tradition of producing fine TV and film scribes, stretching back to the 1950s and '60s with Zack's grandfather, John Whedon ("The Andy Griffith Show," "Dick Van Dyke Show"); and father, Tom ("The Golden Girls," "Benson," "Alice"); and on through older brother Joss ("Buffy the Vampire Slayer," "Angel," "Serenity").

Zack has been schooled in the David Milch tradition for the past four years, starting out as an assistant to Milch on "Deadwood" early on in its first season. He wound up co-writing a "Deadwood" seg with his boss last year, and this year he was a kind of permanent freelancer on "John from Cincinnati." And like the titular character, Zack had good timing throughout. In episode seven, he fell into a bit acting part as Wonderboy, aka the Stinkweed vice president armed with all the research about the company's target demo and its prospects for expanding in e-commerce -- all of which earns him a face full of Linc Stark's bare ass in the memorable mooning scene. In Milch-ian fashion, they wrote the character the day before the shoot and were time-pressed to find someone to play the part.

(HBO's hard-working publicists searched but could only find one production still above from that scene, with Milch at the center, and it offers only a glimpse of Zack's arm, his hand holding a pencil and a bit of his face in the far right-hand corner.)