A lot of hopes and open-source dreams are riding on a plucky little phone platform called Android, and its public debut on a real-live phone happens Tuesday. Those of us at Lifehacker HQ who didn't spring for an iPhone, and even some who did, are eager to see how it performs and, more importantly, what kind of useful apps will soon appear for the open Android. That's not to say we (and many other bloggers) don't have our reservations and lingering questions. We've put together a guide to get you up to speed on the Android platform and the first phone that runs it, along with what we expect, or just hope, to see in Android's very near future.

What is Android, exactly?
Android isn't the "Google Phone" or "GPhone." It's a (mostly) free and open-source mobile operating system that's made to run on all kinds of cell phones, and allow nearly anyone who can program in Java to create and distribute applications for it. Google spilled their plans for Android at the same time—November 2007—they announced that 34 hardware, software, and network companies had signed onto their Open Handset Alliance. In other words, Tuesday's press hoopla surrounds just the first phone to utilize Android, T-Mobile's HTC Dream; unless it's an outright failure, most cell customers can expect to see their carrier hawking an Android phone in the not-too-distant future.

So what will Android look and feel like? We know that, at least with the Dream, phone users will use the flip-out mini-keyboard to enter text, but rely on a prominent, iPhone-like touch screen for navigation. Of course, if an Android developer wants to build a touch-screen keyboard, there's nothing to stop them. One major difference between any Android phone and Apple's iPhone stems from the Cupertino company's patent application for "multi-touch" features; Android users can't resize their screens by pinching and expanding, or use two fingers to dual-finger scroll, but, other than that, you're flipping between work screens with a finger flick, tapping and dragging icons around, and otherwise manipulating your phone world with your fingers.

Don't take our word for it, though. To see Android in action, check out our sibling Gizmodo's in-depth video tour of Android's 0.9 development environment. The Dream and other Android phones may end up looking different (and, inevitably, deeply branded with your carrier's colors and logos, because you obviously can't remember who you pay more than $40 each month to), but they'll share the basic navigation, app-launching and phone-using functions explored in that video.

For a real-world Android demonstration on what is almost certainly a working Dream model, check out this video, shot earlier this week at the Google Developers Event in London:

So, should I get my wallet ready or not?
After showing off the HTC Dream Tuesday, T-Mobile might just surprise everyone by making the phone available that day, but most buyers are expecting to grab it in late October. The comprehensive AndroidGuys blog suggests that T-Mobile might release another handful of Android-based phones, followed by Sprint, and then, possibly, Verizon and even AT&T. Four of the top five cell manufacturers are working on an Android-based model, though, so a strong market response may push the carriers toward open handsets.