Neat Image is a digital filter designed to reduce visible noise in digital photographic images. And there is Linux version!

Tips and Techniques (T&T):

Foam Core Board Photography tutorial. It's a method of isolating a subject from busy backgrounds. Very useful for macro shots.

A short course in using your digital camera and other great short courses on (digital) photography

How to deal with hot pixels

Sturm Photography has a big section on photography techniques

Filters, adaptes etc:

LensMate has metallic lense adapters and multi coated Hoya filtes.

Canon accessories at BugEyeDigital

Cheap Hoya filters (look green) at Baehr Mall eBay store

Filters and other accessories at CameraGear with sample pictures

Flash Clip to diffuse light of built-in flash

Web forums:

DPReview's Canon forum

photography-on-the.net Canon G-series forum

Forum and picture of the day at PowerShot User

Just got my G5!