Rumors of a Facebook phone have lingered since a 2010 TechCrunch article, but they may finally come to a head later this week. Members of the media received an invite to Thursday event at Facebook’s headquarters in Menlo Park, Calif., that simply reads, “Come see our new home on Android.”

While some doubt the viability of a Facebook phone, the social network says that more than 650 million people now access Facebook through a mobile device. It makes sense that Facebook wants itself at the front and center of people’s mobile experience to drive additional advertising revenue; recent updates to the Facebook News Feed were specifically aimed to make the Web experience more consistent with mobile. A full-on Facebook phone seems to be the next logical step.

So what can we expect to see at Thursday's event? According to several reports, the main attraction will be a new mobile operating system powered by Google’s Android platform. Facebook apps like News Feed and Messenger will likely be accessed from the phone’s home screen, similar to the SO.HO launcher that hit the Play Store in beta earlier this month. There will most likely be easy social sharing from anywhere on the phone, probably in a more advanced way than Facebook's integration with Apple’s iOS 6. Instagram, SnapChat and Poke will probably all be there as well.  

According to TechCrunch, Facebook’s experimentation with open-source VoIP in Canada could allow for users to place calls over a Skype-like program. It could then use normal cell connections to reach phones not connected with Facebook.

“Imagine if the regular Facebook app mutated an extra ‘home screen’ limb,” wrote Android Police, which claims to have a leaked ROM of the software intended for Facebook employees. According to the article, the app can turn off the phone’s lock screen, spawn new windows, boot-up Facebook when the phone starts, see what other apps are currently running, control Wi-Fi settings and change system settings. All pretty unremarkable stuff.

More interesting are lines of code that Android Police say are a “dead giveaway” that this app will be available for download in the Play Store, boot-up on HTC phones and other Android devices. From a programmer's standpoint, this means Android phones could download the Facebook update, but the newfangled operating system will come natively on its own device.

It it seems clear that HTC will manufacture the physical phone. This is consistent with several reports, and HTC previously worked with Facebook to develop the Cha Cha, an unsuccessful phone that pushed social integration with a dedicated Facebook button. Android Police reports that the Facebook phone will feature a 4.3-inch, 720p screen, a 5-pixel primary camera, a 1.6-megapixel front-facing camera and no microSD slot. Essentially, the phone looks to be a mid-range HTC phone from a hardware standpoint.

This could support a Salon article that wonders if Facebook will be giving away the phone for free as a loss leader to drive users toward hyper-targeted advertisements. If the hardware isn’t very expensive and Facebook can supplement cell service with its own calling program, it could provide an affordable, no-contract-required alternative to other cell phones.

Are you looking forward to a Facebook phone? Which features are you hoping to see?