|If you shoot RAW, get DPP - it has a drop down box of the styles to you can apply them to the image.
I was playing with them yesterday - it is different than my 300D - on my rebel i had 5 choices for each item and the middle was the default. On the 30D you get 10 choices, and default is like 2 or 3 out of the 10.
standard seems to be the sharpest - it is +1 on the sharpness compared to the other settings (it's 3, the others are 2)
neutral is just that - nothing is boosted.
faithful is more saturated (+1)
monochrome is cool - you can add color filters (liek b&w photography, green, orange, etc) to it or tone it (sepia, etc) and if you shoot RAW you can make it color again.
So i am not sure you can set the 20D up for the same settings as the 30D - there are 5 i think choices and 3 more you can set up as you like for a total of 8.