Many open source projects are happening on Symbian OS. They are a rich source of partially or fully functional code which should prove useful to learn about use of APIs you're not yet familiar with. Please also consider contributing pages to any project that you are currently working on.
Link to Peter van Sebille site with EZoom, EChess, Edoom, EMAME, Scap and ECompXL is changed to http://www.yipton.net/
Will not Xvid and OggVorbis codec be released as built and symbian signed application?