App makers, how do get your mobile app on your Facebook Page? Mixed Media Labs, the startup that aims to be the friend of every mobile developer, has an answer in its latest feature: the Facebook tab.

The Facebook tab can be installed on any Page — it shows up as a green “Download app” icon in Facebook’s left-hand menu — and when clicked, features app content and download options.

A Page’s visitors can even input a phone number to receive a download link via SMS, making this a feature that could finally close the loop between Facebook fan and application user. Developers can also add a “Like-gate” to require visitors to “like” their Page before viewing the tab’s content, as well as customize the tab name and the content inside it.

Launch partners Billboard and Vevo have already installed the tab to promote their mobile applications.

In addition to the Facebook tab product, Mixed Media Labs also offers the suite of tools, designed to help app makers engineer better social media- and SEO-optimized web presences.

“We’re making it easier for app developers to use web virality to get more downloads,” Mixed Media Labs CEO and founder Caldwell told VentureBeat. is Mixed Media Labs second major endeavor. The Andreessen-Horowitz-backed company’s first go-around was with photo-sharing app Picplz, an app that faded in relevance as Instagram picked up steam. Picplz was spun out as a standalone company with a new owner so Mixed Media Labs could focus solely on, said Caldwell, who is most well-known for founding former music-streaming site Imeem, came to be after he realized that the app tools the company was making to monetize Picplz could be worth more than the photo-sharing idea.

“Clearly there’s a market need for these kinds of tools,” Caldwell said.

[Image via César Poyatos/Flickr]