By the size of the image, you're still using 320x240 - make sure you change this to 640x480.
The moons look out of focus- make sure you tweak the focus until the moons are pinpoint dots.
The image itself is overexposed, as you know. What settings did you use? When not using a barlow, there's a lot of light coming in so you need to:
a) Set gain to 0
b) Use a faster shutter speed until the image is not overexposed. That might mean using 1/50, 1/100 or even faster shutter speed.
c) When it's not overexposed, you can start increasing the gain to get the "right" exposure.
d) What software are you using for capture? I highly recommend installing k3ccdtools (v1). It has a "white level" meter on the preview screen, which lets you see whether you are overexposed, as the value will be 255 (bright white). You need to use a faster shutter/adjust gain, until the value is around 200.
e) What framerate did you use? As a general rule, stick to 10fps for now until you get more experience and confidence.
Hope that helps!
Good start though, my first webcam image of Saturn was a bright white oval!
