Here is Binaural Beat freeware I've been using on and off. It supposedly helps people focus, relax, or get in other meditative states.
http://uazu.net/sbagen/
Then there are 'The Four Immeasurables' from Buddhism: Love, Compassion, Sympathetic Joy, and Equanimity. I think these in themselves are more important than mantras.
I have to work on breathing which is probably why I am not great at holding still meditation for long amounts of time yet, but that's also important and apparently the basis of the word Chi. >.>