> I have never heard the term "subpixel Rendering'

Subpixel rendering is being added to a few programs; some of them because of scaling algorithms that I contributed. Take a look at PocketFC or PocketSNES; it uses subpixel rendering to stretch the 240x240 NES/SNES image to 320x240 full screen landscape without making the pixels blocky at all.

The iPaq has 960 subpixels along its long dimension (320 times 3 .... for each of red, green, blue subpixels). By going subpixel and using intelligent color-blending techniques, you can more or less cram a higher resolution into a lower resolution screen.

That's how PocketFC/PocketSNES eliminates blockiness when stretching 240x240 to 320x240 ... Since 960 is divisible by both 240 and 320, it is possible to use 4 subpixels per NES/SNES pixel.

Note, the Casio has its subpixels arranged differently: Along the short dimension of the screen. So the Casio has 720x320 subpixels (240 times 3 equals 720)

Along the dimension of the screen that isn't conveniently divided by subpixels, you will have to do plain old pixel-averaging. But at least along one of the screen dimensions, you can take advantage of the subpixels.

Thankfully, all this can be done in realtime with very little speed penalty. It's starting to happen with more and more emulators, including PocketGB (Gameboy), AppleCE (Apple emulator), PocketFC, PocketSNES.

One example algorithm (for 240x240 scaling to 320x240) is at:
http://www.brighthand.com/ubb/Forum33/HTML/008624.html