I've been playing around with Polaroid, Cross Processing and Vintage Photography looks. Much of which from off-the-shelf sources. Above is an image of mine of Apnea as The Knife Thrower's Assistant, after having been treated to the Polaroin process. Polaroid heroin - it really is addictive. Lots of fun.
Other online Polaroid simulators include the Polaroid site, itself. (Justin Timberlake demonstrates)
Alien Skin also provides some Polaroid and Cross Processing settings for its Exposure 2 plugin.
Some good online tutorials on the matter include this one from photoshopsupport.com on cross processing.
Lot 8 Studios discusses some of his popular vintage look workflow here:
Vintage Feel Basics
Vintage Feel - Additional Effects (The Multiply Layer)
Vintage Feel - Additional Effect - The Hard Light Layer
And popular photographer mojokiss reveals some of his color secrets here
Here is a great discussion on feature film color grading and why exactly so many films these days have cyan-green shadows.
Creating a Summer Blockbuster Film Look
...and I'm looking forward to reading If It's Purple, Someone's Gonna Die: The Power of Color in Visual Storytelling
I tried a mild version of a curves-based cross-processing recipe here. I'm interested in treating the CG as if it were photography. That means lighting it moodily or throwing it out of focus regardless of how much work it took to model and texture - and it also means trying the same kinds of color treatments on the CG/photo hybrids that I would use on a straight photo.
UPDATE 1/18/2010
This Japanese site does an interesting job of turning modern photos old looking.
UPDATE 1/29/2010
Messing around with the free tinting Photoshop plugin from Colormancer. I like the interface and the looks. Here as an experiment I put a heavy sepia layer on top of a green layer on top of a blue layer and used Photoshop blend-if sliders to control how much of each layer is seen.
