Point-and-shoot cameras are fine for posting to web-galleries and forums. If you get really (I mean really) serious about your photos, you could try to get your hands on a DSLR, if you can afford one. All of the photos in this tutorial, however, were taken with a point-and-shoot.
Turn your flash off- it will white out the picture and create all of the shadows we just worked to eliminate in step 2.
If your camera has a manual mode that you know how to use, use settings similar to these:
Aperture: F8 or 11
Shutter Speed: whatever meters properly
ISO: as low as you can get it
White balance: Automatic
Otherwise, automatic mode should get you what you need. If you shoot before sunset, you should have enough light to hand-hold the camera. If you need more light, it will be obvious, because your shutter will open and close very slowly and your picture will be blurry. If this happens, rest your camera on a stack of books or something else handy to steady it. If you finish your cake late at night, substitute a desk lamp for your window by pointing the lamp at the cake and using the lamp exactly the same way as the window. Be warned that the light will be harsher, so you will need to be careful with the reflector.
If you are curious, I have a set of flashes and a pro camera, so here is my typical setup.