I haven't harvested them, but have traded for tons of seed. The seed looks like oreos - black on the outside with a squished cream filling. They're really cute.

This is my first time growing Hyacinth Bean Vine, but from what I understand you have to let the pods ripen on the plant. When the pods split open the seeds are ready. The seeds are as described by bakemom.
I know it's hard, but be patient and wait for your pods to ripen on the vine and split open. Then you will have good seeds.

Let the pods dry on the vine. They will be brown and papery.

Janie