Facebook (FB) has finally cracked the mobile phone market by introducing a package of software that makes Facebook the homepage on Android phones.

The software, called Home, allows users to stay in constant touch with their Facebook friends, even while working on other applications.

Home is “designed around people, not apps," says Mark Zuckerberg, who walked the stage at Facebook’s headquarters Thursday to unveil the latest product, much like Steve Jobs used to when when Apple (AAPL) introduced new hardware.

Home will be available April 12 as a download on many Samsung (SSNLF) Galaxy phones and HTC phones, and as a pre-installed application on the HTC First phone for AT&T wireless customers.

The goal of Home “is to put Facebook in front of you immediately when you turn on your phone,” David Kirkpatrick, author of “The Facebook Effect,” tells The Daily Ticker. It’s “good for Facebook’s long-term social and commercial success.”

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Once the phone is powered up, the “cover feed”— Home’s news feed — will show a picture one of your Facebook friends has sent, much like a screensaver on a computer. Ads are likely to eventually appear as well. When friends post something directed at you, you’ll receive a notification, and when they message you, you’ll see their “Chat Head.” You can open these messages and notifications and respond or just swipe them away and turn your attentions elsewhere.

Kirkpatrick says Home is an “epochal shift” for Facebook from the PC to mobile devices. Cory Ondrejka, Facebook’s VP of mobile engineering, told the crowd at Facebook headquarters Thursday that Home is not just mobile first but mobile best…"the fastest, the highest-quality way to experience Facebook.”

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What will Home mean to the broader smartphone market, particularly Apple’s iPhone?

Apple famously has a closed operating system for all its products, including the iPhone, so it cannot add the Facebook Home interface. “I don’t think Apple is capable of allowing this kind of interference with their whole experience of the phone,” says Kirkpatrick. “If they were to change their policy, it would be good for them. And maybe Facebook and Apple will negotiate some kind of interesting deal.”

The Daily Ticker’s Henry Blodget says Google (GOOG) also has reason to worry. “If you’re Google…your relationship with the consumer has just been disrupted in a major way.”

Kirkpatrick says it’s possible that Facebook and Google and Facebook and Samsung will negotiate deals around Home. “Maybe Samsung and Facebook could jointly develop an entirely new operating system," says Kirkpatrick. No matter what happens, “now everyone else is reacting to what Facebook is doing,” says the Daily Ticker’s Aaron Task.