Friday is the big day—and already, a small group of publicity hounds are camped out in front of Apple's Fifth Avenue flagship store in Manhattan. Also: developers line up submissions for the App Store, and AT&T posts videos on what to expect come launch day.

First up: Headlines began cropping up as early as Independence Day about lines forming in front of Apple Stores for the new, 3G-capabile iPhone.

Well, as it turns out, we're only talking a single line here (in front of Apple's "cube" store on Fifth Avenue and 57th Street), and it consists of about 10-odd environmental activists looking to get into the Guinness Book of World Records.

Members of the group say they want to raise awareness about ... well, a number of things, including "sustainability, affordable housing, energy security, locally-grown food," and "eating right," according to Fortune. Gotcha. Oh, and they may buy a few iPhone 3Gs, as well.

Other than these guys, I haven't seen any evidence (at least so far) of other early lines for the iPhone 3G—and indeed, some predict that the lines won't be as bad as last year, when the iPhone frenzy was at its height.

Meanwhile, AT&T has posted a series of videos detailing how to get ready for the new iPhone, including tips for new and existing AT&T subscribers and a how-to for handing off your old iPhone to someone else. You can also check out this "iReady" checklist (download the PDF).

For its part, Apple has cleared up some lingering questions about how to replace an original iPhone with an iPhone 3G. For instance, new iPhone 3Gs bought in the U.S. will come with their own SIM cards, so you won't need the SIM in your old iPhone. (Non-U.S. iPhone users will be able to use their old SIM cards, however).

Moving along, it sounds like the iPhone App Store is on track for its expected July 11 launch, with TechCrunch reporting that developers have until today (July 7) to submit their application in time for the store's unveiling. Forbes notes that Apple has approved only 16 percent of 25,000 applications, which makes for about 4,000 iPhone/iPod Touch apps at launch. Wow.

And finally, where's the best place to buy at iPhone 3G—at an Apple Store or from AT&T? Carrier reps told Gizmodo that the buying process should be identical no matter which store you go to, although business customers looking to get corporate discounts should head for an AT&T store.

I'll be getting in line myself early Friday to pick up the iPhone 3G; stay tuned for my initial hands-on impressions, followed by a full review.