Ribbit, the mobile development platform owned by BT, announced the winners of its $100,000 Killer App Challenge today, recognizing teams that most effectively integrated voice functionality into apps, web sites and mobile communities. Products created on the Ribbit system are unique in that they span carriers, devices and operating systems — giving the submissions a good amount of freedom, but also the challenge of working seamlessly across platforms.

The competition drew 150 applications from 500 developers based in 30 different countries. It recognized five winners — one grand prize recipient, and four others that topped specific categories. The winners in each category received $15,000, and the grand prize was $30,000. Here’s a quick glance at each of the honorees:

Lucid Viewer (Grand Prize) — In the Media, Advertising and Entertainment category, Lucid Viewer combines video, street view, and calling services to give users a new mapping and communication experience. For example, when you go to the company’s web site, you can scan a city street — just as you would in Google Street View — only now, you can see the identity of the stores and restaurants, and you have the ability to call or text them over the web with one click.

Save a Life — Winner of the Social Networking and Communication category, Save a Life lets users call a batch of their contacts at once. Pulling in features from Yahoo Maps and Google Calendar, the service says it would be ideal for something like a donation campaign or organization news, for which you’d want to disseminate the same information quickly to a subset of your phone book without having to call each relevant person individually.

Sugared Frog — In the Business and Productivity category, Sugared Frog swept in with its hybrid of Ribbit and SugarCRM, allowing users to dictate notes with their voices and have them automatically sent in text form to their email inboxes or over SMS. The most obvious function of the service is to send voicemails to recipients in written form. You can view a demo of the service here. The login and password are both ‘jim.’

SimplePhone — In the Carrier, Network or ISP Integration category, SimplePhone won with its desktop-based Adobe Air application that lets users make voice calls using their computer microphones. It draws from Broadsoft Xtended and SimpleSignal to make this possible. More information can be found here.

Control Your Home, Anywhere, Anytime (CYHAA) — The winner of the breakthrough category, CYHAA (it might want to reconsider its name before commercializing) is riding the mobile energy efficiency wave (defined by companies like Tendril and their phone apps), allowing users to adjust their thermostats, appliances, security systems and other home electronics by making one call and using simple voice commands.