Here is a hatchery that I use: but I use 2 liter bottles.
http://www.youtube.com/watch?v=Y8sNx9zTOnQ
Just turn off the bubbles for about 4 minutes, the egg shells will float to the surface. Stick your baster through to the bottom and suck some bbs. I lay the brine shrimp net over the lip of the hatchery and squirt the bbs into it. You will see them as pink stuff. Then I invert the net into the top of the tank....
Enjoy!!
Jeff.
Note: The author of that video uses a lot more bbs eggs than I do. I try to use enough for two days feeding, and have a new batch hatching on the second day so I have a fresh supply of NEWLY hatched bbs when that one is done! I do seem to have a few stragglers in the batch when I dump them If you try to stretch the batch too long they all seem to die and go bad anyways.