It’s no secret that Boston is a hotspot for mobile. Nuance, T-Mobile, Apperian, Texterity, Houghton Mifflin Harcourt, Vivox and others all shined this week on the mobile front. Here are six great new iPhone, iPad, and Android apps that were built, powered by, or recently released here in the Hub.

Nuance FlexT9

This $4.99 Android app completely transforms your Android smartphone or tablet’s keyboard, giving you flexibility as far as how and when you want to use it. Nuance FlexT9 is listed in the Amazon app store and built by Burlington-based speech and image solution powerhouse Nuance. The app provides you options to use your keyboard in four different ways: in the standard tap to type way, by speech (using Nuance’s speech-to-text Dragon Dictation technology), by tracing and gliding your finger over characters (using Nuance’s T9 Trace technology), and writing (using Nuance’s T9 Write that lets you use your finger to handwrite letters).

FlexT9 is a pretty genius solution that capitalizes on mobile as a tool being used in more and more situations. The app truly puts you in the driver’s seat, allowing you to optimize the most convenient and efficient way to use your keyboard on a situation-by-situation basis – whether you need to quickly speak to search or take notes in standard fashion on a tablet using your finger as the pen.

Bobsled for Facebook

T-Mobile recently released an application geared at Facebook users called Bobsled, which allows you to call and send voice chat messages to any of your Facebook friends over VoIP (voice over internet protocol). The app is powered by Natick-based Vivox’s voice platform VoiceEverywhere, which is aimed specifically at the social web. In addition to the calls, users can also send voice messages privately or publicly right on their friends’ Facebook walls and message inboxes.

Vivox’s technology allows T-Mobile to boast that Bobsled is the world’s first free, one-touch Facebook calling application. T-Mobile is branding Bobsled as bridging the traditional telco’s with the internet world, saying, “it positions T-Mobile as a provider of cloud-based communications services over the the Internet.” Judging by the Bobsled site, it seems that Facebook is temporarily limiting Bobsled’s functionality within Facebook… but you can still enjoy free calls.

The Photographer’s Eye

Priced at $24.99, this iPad app is all about “composition and design for better digital photos.” It is based off from the bestselling book The Photographer’s Eye by internationally recognized author Michael Freeman, which has sold over 300,000 copies worldwide to those interested in digital photography.

The app is the digital version of the book – taking full advantage of the iPad’s high-resolution screen and opportunities to present the book through new media. It features video intros, interactive diagrams and other elements, and recordings from the author. The Photographer’s Eye iPad app was released last week by Waltham-based Focal Press.

U.S. Treasury’s EyeNote

Few people know that the United States Department of Treasury exclusively prints its dollar bills on paper from a company in Western Mass. And it seems they’re continuing to put their trust here in Massachusetts as money goes more digital. Yes, the U.S. Treasury has released an app called EyeNote, aimed at helping the blind recognize currency values by using advanced image recognition.

Behind the app: Boston-based Apperian, with its EASE cloud platform that allows businesses to create, deploy and manage applications for iOS devices (and soon Android). The U.S. Treasury is the first Apperian client to leverage its image recognition engine. With EyeNote, anyone visually impaired with an iPad, iPhone or iPod touch can use the app to take a photo of a denomination and have its denomination communicated back.

Broadcast Engineering Magazine

Southborough based Texterity, behind the recently released Disney Family Fun iPad app and 120 others, has just released another magazine app. This time it’s for Broadcast Engineering, published by Penton Media in NYC — and this time for Android.

Broadcast Engineering is a monthly publication covering TV, production, cable, satellite and other other broadcast technologies. Published monthly, this magazine is aimed at professionals, operators, engineers, and executives in the traditional media industry. The magazine features current and past issues through February 2011, allowing you to bookmark favorite articles and share comments socially with other readers. The publication released iPad and iPhone versions in March, and is following up to reach Android users.

HMH Fuse: Algebra 1

Another publisher we’ve seen dabbling in the world of tablets is Boston-based Houghton Mifflin Harcourt (HMH). Just last week the company released an Algebra 1 iPad app based on its HMH Fuse platform, aimed at school districts, teachers and curriculum coordinators. This app provides a core algebra 1 curriculum based off from the Hold McDougal Algebra 1 book, already in many classrooms today.

The app features animated instructions, practice questions, the ability to take and save notes, over 400 video tutorials, and a feature that allows students and teachers to connect – such as access to assessment/quiz data based on a students activity within the app. HMH has released a website to go along with the release of the iPad which features webinars and a video demo. Priced at $59.99, HMH plans to also release Geometry and Algebra 2 apps later this spring on the HMH Fuse platform.