Jayani is singing the mantra Om Namo Bhagavate Vasudevaya. This mantra is worshipping Krishna. He is worshiped as the eighth avatar of the god Vishnu and also as the supreme God in his own right. He is the god of compassion, tenderness, and love.
There are many english seminars every year in the different ashrams of Yoga Vidya. You can find them all by clicking here: yoga-vidya.org/english/seminar/.
You can get to other mantra's here.