This looks really nice. I've been experimenting with rolling my own filters using imagemagick, although I ended up piping my photos to a server I run via pixelpipe and dropbox, running the filters remotely and pushing the photos back to the phone, due to the amount of processing power some operations require.

A few tips for effects:

You can make curve presets in any app with curves and apply those curves to a grayscale gradient to create a look-up table that is easily applied to images.

For a basic technicolor two-strip look, simply copy the green channel of a photo to the blue channel and do some curve adjustments.

One effect I've found quite nice is the bleach-pass look: take a grayscale version of your photo with increased contrast and composite with the original (or, for better results. a colour-corrected version of the original) with the soft-light or hard-light blending mode.

Here's the result of one filter I cooked up, combining a technicolor-esque colour scheme with the bleach pass look and a grain+vignette layer on top:
http://img815.imageshack.us/img815/4...echnicolor.jpg