Mum had a butterfly release at her wedding recently but she didnt actually release the butterflies until after the reception.
She and my StepDad wrote poems, or tributes to each member of the family a butterfly was being released for, (in this case we had eight of them) with a photograph and they were in little frames near the vase that the butterflies were being held in.
That way, all of the family/friends could see the idea behind it, who they were for, etc.
Mum and S-D chose to release together after the ceremony

But i guess it all really depends what aspects of a release you're looking for..