Since my successes with third eye mediation earlier this year I've been experimenting with mediation on the other chakras. The table below is a result of my own observations as well as influenced by numerous writers such as Ted Andrews in Sacred Sounds and GRS Mead's Simon Magus (Mead, G.R.S. (1892). Simon Magus. Theosophical Publishing Society) which contained a copy of Simon Magus's Diagram of Simonian Aeonolgy which is also on Wikipedia http://en.wikipedia.org/wiki/Simonians and further explained by Simon's "Great Declaration". http://www.examiner.com/article/the-great-declaration-by-simon-magus gives a good overview of the Great Declaration.
I hazard to say that the practice of yoga and meditation are not religion but rather experiential. As such the experiences of people around the world who undertake this type of exercise, by whatever name they choose to give it, are manifestly similar. For instance mediation on the lower chakras generates a kind of warmth at the base of the spine. It also stimulate the sex hormones. Yoga practitioners seek to raise this energy up the spine to activate the energy centers above. If you have blockages immediately above this chakra then you can easily get bogged down in hedonistic stuff and make no further progress. I think a better approach might be to start with heart chakra mediation then work progressively outwards, over some weeks, with the chakras either side. In this way the complementary nature of say the solar plexus and throat chakra and then the hara and third eye keep you balanced. Finally include work on the outer root and crown chakras, connect and balancing them. I got my inspiration for this polarity approach from Esoteric Anatomy by Bruce Burger. Once you are sure you have adequately worked with and balanced all your chakras then you can do a bottom from the top meditation without fear of getting stuck at any points along the way. The ultimate aim being to connect Shiva with Shakti. I sometimes use an electronic guitar tuner to help me sound the right note for each chakra.
I make no claims for the following table being definitive. It is purely what I've worked out for myself through insights and what I've experienced, tried and read. I've tried to take the jargon out of it. A lot of people get the location of the heart chakra wrong, thinking it to be lower down on the sternum but being a shiatsu therapist I go for where the indent is on the sternum. Also I believe that the location of the root chakra is slightly different for men and women but I'll leave it for someone braver than me to explain that - look it up on Google! For more information, but full of jargon, try the explanation on Wikipedia http://en.wikipedia.org/wiki/Chakra.
Finally: the number values I give relate to sacred geometry, not the number of petals on each chakra as stated in the Hindu tradition.