I have seen a few tutorial on specific effects but I have not found any kind of script/plug-in/tutorial that would have them all the ones on the iphone app listed. I don't mind doing it by hand with a tut, but I am just not sure how to get all the different effects other than by 'eyeballing' it, which is not a good idea in my case.

I would use the app to take pictures with each color effect applied, and without (I think you can save both).

Then bring them into GIMP, and use something like elsamukos awesome "Get RGB Curves" plugin to extract the color curve changes to produce the effect.

You'll need to account for the vignette that is applied, but the curves should get you pretty close to what you want right off the bat. I might fiddle with the curves to smooth them out, though (set the curve type to "smooth" for each channel).

I'll write up a tutorial and package up all of the effects that are applied shortly (busy at work this week).

Here's a list of the Instagram effects with a short description that may help with curves, channels, etc.
http://en.wikipedia.org/wiki/Instagram#Effects

An alternative view of the use of instagram/hipstamatic type of effects:

"Has Instagram made everyone's photos look the same?" : http://www.bbc.co.uk/news/magazine-17667891

Although, given the membership of this forum, I don't think there's any danger here of universal conformance to a fixed set of effects

Kevin

@patdavid...Great_ a tutorial about this will be awesome!!! I do use one of your tutorials on matching colors, where you pick points on each pic and then match up the curves. It works quite well, I was just looking for something quick and easy to use on pics that are on my computer (as opposed to taking a new pic with my phone). For now, I am using your tutorial.
@odin...that is a good resource, it will help a lot!
@paynekj...this is just for some fun pic effects as part of a larger project, and some of the pics will be tweaked using G'Mic, others by hand with basic Gimp filters. I agree somewhat with the article, that instagram can be overused but also can peak interested in the how of it al!
Very useful insights and responses, thanks!

I've often wondered about the purpose of Instagram.... I always assumed it was a way to "artistically" degrade a photo taken by a poor quality camera to "hide" the fact that it was a poor quality camera taking the photo

-Rob A>