Here are some of my current projects:

Open Camera (Android) Open Source Camera app for Android smartphones and tablets. (Started 2013)
Erebus (Windows, Linux, Nokia Symbian, Android) An Open Source 2D real time Role Playing Game. Over 110,000 downloads! (Started 2012)
Vision 3 (Windows, Linux) A DirectX and OpenGL based Open Source 3D game engine. (Started 2000)
Gigalomania (Windows, OS X, Linux, AROS, Nokia Symbian, Maemo, Meego, Android) An Open Source 2D Real Time Strategy game, for PCs and smartphones/tablets. (Started 2003)

And my completed projects (although they may occasionally be updated):

Conquests (Windows, Linux) A Open Source turn based strategy game (similar to Civilization), which uses Vision 3. (2009-2012)
Daleks 3D (Windows, Linux) A simple game, which uses Vision 3. (Started 2002)
Wifi Remote Play (Nokia Symbian, Android) Remote Control app for Nokia Symbian and Android smartphones/tablets, allows control of Media Player Classic and VideoLAN Client over a wireless connection. Open Source. Downloaded over 2.5 million times since 2012! (Started 2010)
QBall (Nokia Symbian, Android, BlackBerry PlayBook, Windows, Linux) Breakout clone for Nokia Symbian, Android and BlackBerry PlayBook smartphones/tablets, also available for Windows and Linux. Open Source. (Started 2010)
Sunrise (Nokia Symbian) App for Nokia Symbian smartphones to calculate sunrise and sunset times based on your current location. (Started 2010)
Livejournal Qt (Nokia Symbian) Livejournal client for Nokia Symbian smartphones. (2012)
image2svgt (Windows; useful for Symbian development) Simple utility to embed raster/bitmap image files into SVG Tiny (and SVG) format. Open Source. (2010)
WinLaunch (Windows/AmigaOS) A simple utility for launching Windows programs from within WinUAE. Open Source. (2003)

And some really really old stuff...:

NewsCoaster [Link to external site] (AmigaOS) An Open Source newsreader. (Started 1999)
Amiga LiveJournal (AmigaOS) A LiveJournal client. (2002)
Web Colour v1.2 (Windows, AmigaOS) A simple program for creating coloured text in HTML. (1998, 2000)
Vision 2 (Windows) (1999-2000)
Vision for Java (Java) (1999)
HTML2Guide v2.0 (AmigaOS) HTML to AmigaGuide Convertor (1999)
Vision 1 (AmigaOS) (1998-1999)

Please contact me at mark dot harman at ntlworld dot com .