If you haven't heard yet about Dr. Horrible's Sing-Along Blog, the new project from Joss Whedon (Buffy the Vampire Slayer, Serenity, and more), it's a new 40+ minute musical in three acts that was produced independently by Whedon's company, Mutant Enemy, and debuted on the web this week for a limited run. You can watch the three parts for free until midnight tomorrow (Sunday) on the website, or buy them in the iTunes store, where they've ruled the TV charts all week.

I won't review the musical here -- that's already been done well by USA Today, NPR, NewTeeVee, Time, Salon, and hundreds of fans over at Whedonesque -- but I'll just say that as a fan of everyone involved, it's even better than I hoped. And it plays great on anything from an iPod to a big screen -- I watched all three acts on my AppleTV and definitely got the kinds of laughs and thrills you want from the best television.

Joss Whedon has possibly the most dedicated and organized fan following online of anyone working in Hollywood right now -- making him a natural person to see if there's a way around the Hollywood system. Take for instance, his movie Serenity, which "only" made around $40 million at the box office (about equal to what the movie cost to make), but also mobilized its fans so well that it opened as the #1 movie in the country and debuted at #1 on Amazon's DVD chart. Buffy and Angel are still going strong on DVD box set sales, Dark Horse's Buffy comics were some of the top-sellers of the last year, and until Fox put the kibosh on it, Buffy: The Musical fan sing-alongs were selling out in theaters all over the country. Not to mention hundreds of fans showed up to support Joss and his colleagues during the WGA strike. That's the kind of cult audience you should be able to build a direct relationship on the Internet with.

The first act went up late Monday night, was immediately slashdotted, and any site associated with the show quickly crashed, with DrHorrible.com clocking over 200,000 hits per hour. With the series available nowhere else but iTunes (and a couple of lower-quality torrents), I'm sure it had plenty of paid downloads and made a good dent in the six-figure budget of the production (Whedon hopes to at least break even). According to Joss's master plan, there will be a pretty cool DVD on the way soon after, and I've gotta imagine fan singalongs in a theater near you and a soundtrack album can't be far behind. The songs are great -- especially "Cannot Believe My Eyes" in Act II.

You might know Felicia Day from the Buffy series or, more recently, the great new internet show The Guild, which she created and launched this past year and scooped up a raft of awards and accolades, not to mention lots of fans here at Next New Networks. She costars with the incredibly great Neil Patrick Harris and Nathan Fillion, but the real thrill is watching Felicia in it because she's now one of us, and realizing that she's helping make Harris and Fillion and Whedon and every person involved in the production one of us, too.

Enough already -- make some popcorn, watch the show, and see what Internet TV can be. With both this and Nite Fite debuting to lots of fan love, I'm starting to wonder if I'll even have a cable subscription in a year.