The IPad Forum is a community of members from all walks of life and from all over the world coming together to share our experiences and to help each other learn about this wonderful piece of technology the Ipad. There is a wealth of information already here in the many threads we have so doing some searches will answer most of the questions you have. If then you cannot find the answer you are seeking then by all means post your question. There are many friendly and informed members here only too willing to help you.
U can only do this if u bought it in itunes, if tha music was downloaded and transfer from itunes to ipad and u want to do it backwards, u cant, only music bought on itunes will be available in all devices including itunes on ur mac or pc.