I like David Garrigues' teaching on jumping through in the Ashtanga vinyasa. It's all about the crouch and springing forward. In this video he offer four options, from stepping it through, to using blocks, to the full jump-through. It's about gathering leg-hip energy with the crouch and then releasing that energy forward - woosh!
We worked on this a bit in my class today, which btw, is Sundays 11:00 am at Yoga Studio Ganesha.