Video games played on a mobile phone is what we called as Mobilegames, these mobilegames can alsobe played on smartphone, PDA, handheld computer and on portable media player.
The above list does not have includes games played on handheld video game systems such as Nintendo Wii, PlayStation Portable, PSP. PS3, Xbox360 or Nintendo DS.
Game that was pre-installed for the first time in a mobile phone was Snake on selected Nokia models and you can see the sucess whole gaming industry has gone into tremendous change looking into the demand of mobilegames.
 Snake and its others version become the most played videogame on this world, everyu person who was having a mobile played snake game and enjoyed a lot till date recently i buy E71 that also include the snake game by the name tetris 2010 awsome i cant share the experience in words it remeber me ten year back whem I played snake for the first time in Mobile i felt same energy and positive aura same like first experience.
Mobilegames are played using the latest  technologies incorporated on the mobilephone itself but now days some games requirement is like your GPRS should be enabled before downloading games online common best games are cricket online, and dress-up barbie game, so ask your service provider to enabled GPRS into your mobile phone so that you can play online mobilegames.