I actually did mine by hand and with a coarse sifter last year. If you leave it in the sun for awhile, they will burrow down and you can take the top layer, than wait awhile, take the next layer as they try to get away from the sun.

I invited my little granddaughters over. We sat around a child-sized table and had a "worm hunt". It was tedious but it also kept them busy.

Otherwise, I haven't found an easy way to separate them.

I have not tried it, but I have read that placing some window screen over the compost heap and topping that with fresh vegetable cullings will help hungry worms squeeze through the windows screen and into the food on top of the screen and make it easy to empty your bin.
The key is to keep the worms a bit hungry for a few days so that they are encouraged to migrate.

Just make a soil sifter. Get yourself some 1 x 2 lumber and some relatively fine gauge wire mesh screen. Make a frame, attach the mesh to it, and voila. It will get all but the smallest worms.

I spread my vermicompost on a table covered with plastic, the worms don't like the light so they go deeper into the compost. I take about an inch off the top every 5 minutes. After a half hour or so, your left with a pile of worms to put back into your bins.

I don't mess with it. I just leave a couple of inches of compost at the bottom of the bin and there are enough in there to reproduce like crazy by the time I'm ready to empty it again. I end up with a dozen per shovel full. NT

I don't have a worm bin, but there are countless worms in my compost bin. I just let them move to my garden beds when I augmented with compost. They do fine in my garden too so I don't worry.

Here is a link that might be useful: Sinfonian's garden adventure