Mobile

K9 is a stable and popular email client for Android mobile devices.

A free software project created by a strong community of volunteers, K9 makes it easy to add multiple accounts and to deal with large amounts of incoming emails. It has recently added support for GPG encryption, which is a common way of sending encrypted messages.

For more information about encryption, consult Tactical Tech's Security-in-a-box guide.

The proliferation of mobile computing devices in recent years has meant that websites can no longer remain static or stick to one screen resolution or aspect ratio. Your organisation's website should be optimised for a variety of devices and resolutions, to reach the widest number of users possible. But how to test your website when you don't own every device? Screenfly, a great tool from QuirkTools, allows you to virtually view any website in a variety of resolutions. There are presets for common devices, or you can set a custom resolution or rotation.

Bambuser is a live video service that allows you to capture, upload and store video from a mobile phone or webcam. You can set up broadcasts, like channels, and share them publicly using social media, or share privately with just certain users. You can also view videos on your phone, and chat in real time. Geo-tagging is possible. With certain platforms, you can also save a recording and upload it at a later time.

Magpi (formerly Episurveyor), is a web-based application that enables anyone to create a data entry form online, and then use this form to collect data on a mobile device. Once collected, data can be uploaded to the Magpi website for analysis or export. The Magpi mobile app is available for iPhone, Android, Blackberry, and Symbian phones. Simple information can also be collected from ANY phone using SMS. The form designer is a web application which you can access via your browser; no installation is needed.

Ushahidi is a highly flexible platform for information collection, visualisation and interactive mapping. It was originally developed to map incidents of violence during the Kenyan elections in 2008. Now Ushahidi (meaning 'testimony' in Swahili), is widely used in many different scenarios, including emergency response management and citizen media. See a full list of deployments.

FrontlineSMS allows you to send and receive text messages over a mobile network.

Browser-based and built to run on Windows, Mac and Linux, FrontlineSMS can send text messages via phone, modem or online SMS aggregator.

Using Frontline SMS, you can deliver announcements, conduct polls and automate replies to incoming SMS. You can also visualise incoming data, helping you to quickly understand the results.

ZXing (pronounced 'zebra crossing') is an open source barcode image tool. It can be used to create and read barcodes and QR codes. A QR code is a printed square of blocky pixels which can be scanned by devices including smart phones to point users to a web page, contact details or other information. The ZXing project runs an online code generator which allows you to create QR codes which can contain many different kinds of data.

Skype is the most popular service around for voice calls over the internet. You can also use live text chat and send files. Many international organisations rely on Skype to reduce their costs, using it instead of the telephone. It makes online collaboration between global grassroots communities easier, as it is both cheap and universal, supporting calls to landlines and mobile phones.

WordPress is a tool used to create websites and blogs. There are two ways to use WordPress: you can download the software from wordpress.org and install it on your own server, or you can sign up to use it as a blog service at wordpress.com. If you use the blog service, you have less customisation options, but the hosting is free and the technical side is taken care of, so you can focus on content.

HandBrake was created to convert DVD discs into smaller video files suitable for viewing and sharing on the Internet. This is called 'DVD ripping'. HandBrake is popular, and is available for many different operating systems. There are now more features including transcoding, which means changing one type for video file into another. This is very useful for video makers wanting to make their projects small enough to fit on a CD, or to share online or on a mobile device.