Hello. I'm trying to build a system that takes a photo when a predefined event occurs (say when motion is detected). I'd like to attach a camera module to a circuit board. If the Arduino cannot handle such projects, what else should I be looking into? Thanks a lot.
Have you seen Trigger Trap?
https://triggertrap.com/
If the arduino has any part in handling the picture data then no. If it just triggers a camera then yes you can do it.
I don't think the trigger trap would work for me, since I don't want to have a separate stand-alone camera. What I want to do is have a camera module (http://goo.gl/wjzRN) be part of the circuitry, triggered when an event is detected, and possibly upload the picture to the web, via an ethernet shield or something of that sort. If the arduino is unable to handle such tasks alone, what other boards should I be looking into? Thanks.
That is not the sort of thing an arduino can easly handle.
Look for something like the Bengal board or raspberry Pi.
Alright. Thanks. I'm having some trouble finding the Bengal board, but I'm looking into the Raspberry Pi.
I found the Beagleboard* though.
You want something that can at least host a webcam 
http://www.sparkfun.com/products/9947
The USB Host Shield contains all of the digital logic and analog circuitry necessary to implement a full-speed USB peripheral/host controller with your Arduino. This means you could use your Arduino to interface with and control any USB slave device - thumbdrives, digital cameras, bluetooth dongles, and much more!
Or you could spend over $100 on a Beagleboard.
It is one thing communicating with a web cam, it is another doing anything with the image data with the small amount of memory you have on the arduino.
Sorry I did mean Beagle board, dam auto spell corrector.
Does the shield have an SD card? If not, could the Arduino could trigger +and+ store?
Would SPI be fast enough? And if so, do a bit of contrast/brightness adjustment in the pipeline?
It might work, at 320x200 or less.
Lots of ifs buts and maybe's here. Answer is that no one to my knowledge has done it yet and expecting a complete beginner to break new ground is asking a bit much.
Attempts have been made with a Jpeg camara module but from what I recall the resultant files written to the SD card can not be decoded.