One of the main reasons given for getting a Canon G9 is its capability to shoot in Raw mode. A Raw file is the digital equivalent of a film negative and there's a lot that can be done with it. But what software to use for the digital development of a raw image file?
Although Canon's editing software is bundled with the G9, there are other programs considered much better -- especially Adobe's Photoshop. The current version of Photoshop is "CS3". CS3 develops the raw image files with Adobe Camera Raw (ACR). ACR now has been updated to process Canon G9 Raw files.
Adobe Camera Raw can be intimidating. There's a new book that should be very helpful: "Camera Raw with Adobe Photoshop CS3" by Bruce Fraser and Jeff Schewe published by PeachPit Press. I got mine through Amazon. Here's a review of the book by Michael Reichmann.