Yep, that's how you do it. Sometimes, when I want to post one of my pictures that I took, and want to post it here online, i open the image using Windows Picture and Fax Viewer. This app automatically resizes the image to fit within the application's borders. Since my screen resolution is 1024x768, all I have to do is press the PrintScreen key, paste into photoshop (new document automatically creates a document of the correct dimensions), and crop the image to my specs, and i don't need to resize it myself to 800x600 (although sometimes i want to show the quality of the shot, so i might resize it to 1024x768).
Well, looking forward to seeing what you have in mind!
To browse some of my photos: <Links will open in new window(s)/tab(s)>
My BirdForum Gallery
My Flickr Gallery
Last 2007 year bird/lifer: Lapland Longspur (#51/136)
Last 2008 lifer: Red-Headed Woodpecker (#137)