I found this project on Pinterest, where else? It's pretty self explanitory, but the directions were in Dutch so I googled "perler bead bowl" and got a bunch of hits. The one I kind of followed was this one. This was easy enough for Sabrina to help me with, but I still had to help get the beads in a single layer.
Some tips I found around the net:
The oven temp does not have be be exactly at 400F. I did a different batch at 300F and it worked just the same.
Use a butter knife or plastic scraper to get the beads out of the bowl.
Use any dish that can go in the oven for different shapes and sizes. I used a small IKEA baking dish for mine, Sabrina used a Pampered Chef small glass measuring bowl. My second one was a cheap silicone dish in the shape of a heart.