Hi!
I usually do some patch-contributing for the DOSBox project, but this time I
created something which is useful for all 2D emulator-like SDL projects:
high-quality scaling using your graphics hardware. Imagine hq2x, hq3x, hq4x,
hq-any-x, executed by your 3D graphics card.
The best of it: There’s no coding to be done. The latest version of OpenGL-HQ
is a binary-compatible patch for SDL, which means any SDL app can use
OpenGL-HQ instantly, without recompilation. You just swap your SDL.DLL (or
whatever your OS uses) and get gorgeous scaling surpassing anything currently
available (if you’re a hq2x/3x/4x lover, that is). Well, to be honest, it’s a
patch against the 1.3 branch, which is highly experimental, but which
nevertheless works for a lot of people.
For a full list of features and requirements, visit the OpenGL-HQ homepage at
http://garni.ch/dosbox/, it includes screenshots, documentation, a
precompiled win32 SDL.DLL, and full source code.
Primary support location is the dosbox forum (find the direct link on the
HP), but please be sure to read the full README, there are some inherent
limitations, and the dosbox folks already did a good job finding out the most
frequent questions.
Oh, and feel free to mention this to other SDL-based emulator projects as
well. I don’t know them all 
Have Fun!
Joerg–
CU
J?rg