I like to etch a picture on the side of my case of a pattern that i have on my pc. (Case is black) How can i get a outline of the pattern on the panel to etch of the black paint to reveal the metal underneath.
Draw your pattern on a piece of paper with a pencil. Place the paper on the surface you want to etch drawing-side down. Rub the white side of the paper to transfer the graphite. That's kindergarten stuff, really. You should test to see if the pencil will stick before applying.
If it is engraving you mean, then you may get some inspiration from this http://www.bit-tech.net/modding/2006/02/14/spiderman_by_gotall/1.html Look on the second page. A bit advanced, but you can start simpler if you want. Just gives you some ideas maybe
You could put masking tape on the panel, draw your design on the masking tape, and then etch through the tape, then peel it off when you're done.