There is currently no audio button or functionality on most Bible reading plan pages. The exception is the Daily Audio Bible reading plan, which features accompanying audio and is located here: http://www.biblegateway.com/reading-plans/today?plan=9 .
The only way to hear the audio for daily readings from other reading plans is to manually look up the passage you want to hear using Bible Gateway's main search. We realize this is an inconvenience and hope to improve this situation in the future. In the meantime, we ask for your patience.