There are some spiritual books by Pundit Sri Ram Sharma Acharya available online
now:Some of the titles include:
"Extrasensory potentials of mind" , The absolute law of Karma" , Music- the
nectar of life", " Integrated science of Yagna", "Eternity of sound and
science of Mantra", " Sleep, Dreams and spiritual reflections" "Life beyond
physical Death", "My life, its legacy and message", "Mahapurusharan- A Unique experiment of collective consciousness" and many more at
http://www.awgp.org/english/books/books.html
Also, there are lectures and other material at www.awgp.org and www.dsvv.org

All of Osho's( Rajneesh) lectures ( in english and hindi) and many of his books in english on spirituality ( controversial but
thought provoking) are available at www.oshoworld.com for free
download/listening. Shiv Sutra in Hindi is very good. ( Click on Discourses then select Hindi and find Shiv Sutra under S). You can also start with his lectures on Kabir or Guru Nanak.

Also, there are some very nice lectures / articles on various vedantic subjects by pujya swami Dayananda and his disciple swamis at
www.avgsatsang.org

Hope you enjoy these sites..

Vipul..