A handy tool for web developers is Dynamic Drive's Gradient Image Maker. Creating gradient images is a basic thing that a web developer has to do and there's no need to fire up Photoshop for something like that. Microsoft Paint can be used to create gradients, too, but a dedicated tool beats that hands down. :)
Another nifty tool, possibly for selecting the colors for your gradient, is Iconico's ColorPic. It can be used to pick a color anywhere from your screen. It's got an adjustable magnifier, you can nudge the mouse cursor pixel by pixel using the arrow keys, and you can select the average color of a small area of pixels in case selecting the color of a single pixel is not desired!