As of v093, Higan (previously known as bsnes) includes a new shader format based on OpenGL 3.3 / GLSL 1.5. This format is nice, powerful and roughly as flexible as RetroArch's Cg support. Hyllian, aliaspider and I set to work converting many of the most popular shaders to the new format, available from the Quark Shader Github repo.
If you're not familiar with git, you can download the full repo by clicking on the 'Download ZIP' button in the right-hand margin.
To use these shaders, place the entire *.shader directory into your Video Shaders directory. One caveat: the handful of shaders that utilize motion blur won't work with v093, but should be functional with v094+.