1. Download a free graphic design program, I used Gimp.
2. Drop a Coachella poster of your choice into the program. Use the paint brush to brush out all text, and if the poster is multi-colored (like 2012), use a gradient brush and go line by line, selecting colors that are in the back of each line of font. It might look a little janky, but when you put text over it you won't really notice.
3. Bring the poster into iPhoto. Change the tone, exposure, etc. of the blank poster until you get the color and vibe you are looking for.
4. Next, use Word. Drop the edited photo in, and use WordArt boxes to write text on top of the Coachella photo. Use the Eurostile font, play with different sizes for different billed names, and use the "circle" from Symbols to make the dot between names.
There you have it. Took me only a couple hours over a week to make mine, and I had never used a graphic design program before so most of that time was spent figuring out how to do certain things. If you have, it should be child's play. I was surprised how simple it was.
I will literally get nothing done for the rest of the day. Thanks a lot.