OpenGL ES is a subset of the OpenGL API used in embedded devices. It is used by Apple's iPhone, Google's Android, Nokia's Maemo, the Sony Playstation 3, the Pandora handheld and other devices.
OpenTK now offers experimental support for OpenGL ES profiles 1.0, 1.1 and 2.0, which roughly translate to OpenGL 1.3, 1.5 and 2.0 respectively. This includes inline documentation but excludes strongly-typed enums, which will be added at a later time. There is also no support for constructing contexts through EGL, however it should be possible to use an external GL ES context in conjuction with OpenTK. Finally, the bindings are untested - please file any bugs you encounter.
If you are interested in helping out, testing or porting (esp. to iPhone and Android), make a post!