NVIDIA has released a set of OpenGL 4.3 drivers for Windows and for Linux.
The driver support provides beta support for OpenGL 4.3 and GLSL 4.30 on capable hardware.
For Linux, the version number R304.15 is not the same with the drivers for Windows: R305.53.
All ARB extension specifications can be downloaded here: this page.
For OpenGL 4 capable hardware, these new extensions are provided: ARB_compute_shader ,ARB_multi_draw_indirect ,ARB_shader_image_size ,ARB_shader_storage_buffer_object
You can download all drivers from here.
