I am really into photography and digital imaging, so I thought I would look up some tutorials on deigital editing. I found this site which seems quite useful.
It is called 'Kitchen Wench' and is a mostly personal site which documents a lady's cooking, recipes and photography.
The url is:
http://www.insanitytheory.net/kitchenwench/
Here is an excerpt from the 'about me' page:
"The eldest of three children, I was born in South Korea and immigrated to Australia with my parents at the age of 4. Having grown up mostly in Australia (with a brief 2 year stay in Korea when I was 14 - 16), I’ve grown up in a strange hybrid existance of Korean and Australian attitudes and mentalities, which very much crosses over into fields such as my cooking - I love my kimbap just as much as I do a good chicken parma or pavlova!
I keep this site running mostly for myself, in order to document my progress in both my cooking and photography, and also to document my mother’s Korean recipes for the future - for both myself and those who browse the internet in search of good, home-style Korean recipes
My equipment is simple - I use a point and shoot camera, the Canon Powershot G7, and I do most of my photo editing in Adobe Lightroom and Photoshop."
http://www.insanitytheory.net/kitchenwench/about/
Here is the tutorial on digital editing basics:
"Firstly - remember, with photo manipulation, LESS is MORE. Especially if you’re not sure of what you’re doing and using a destructive editor (an editor that makes the changes to the actual file, thereby ‘destroying’ the original data). If you’re using one of these editors, never ever make the changes to your original photo, instead you should create copy the file to a new folder (good idea to keep all the edited photos together) and make the changes to the duplicate file. That way, if you muck something up, you still have the original photo to create a new copy from.
Secondly - photo editing is meant to enhance the image, it is not some kind of voodoo magic, it cannot turn a crap photo miraculously into a good one. You should always try and take the best photo possible with your camera, paying particular attention to focus/sharpness, white balance and exposure, this will mean you have to spend far less time fiddling with the photo in post-production and the editing process will be far less painful.
Thirdly - another camera related point is that you should always take your photos at the best quality and highest resolution possible. Why is that? Because this means you’ll experience less of a drop in quality when editing and resizing the photo later on! Sure, the file sizes may be pretty big (each photo off my camera is roughly between 6-10 mb each) but I think that in the end, its pretty worthwhile!
Fourth - STAY AWAY FROM OBVIOUS EDITING! One thing that I notice a fair bit is an almost obsessive overuse of the blur and smudge functions that must image editors offer. Whether it is to try and simulate DoF (depth of field) or blur out an unattractive background, the results do very little for enhancing the natural beauty of the food you’re photographing, and often serve as more of a distraction. A sheet of thin white cardboard or a roll of wrapping paper is just a few dollars, and is a better alternative to hand-blurred photos. Another thing that really gets my goat is over-lightening, but I’ll discuss that a bit later.
Fifth - Make sure your monitor is displaying colours probably, i.e. calibrate your screen. Now, my current LCD monitor has an iffy white point which I, for some reason, can’t fix, so I know that images that I view on my machine will probably appear slightly differently on others or when printed. This site has a great, easy to understand series of pages on monitor colours and calibration which is a good starting point for you."

http://www.insanitytheory.net/kitchenwench/2008/01/06/digital-editing-101-working-out-the-basics/