I've begun to experience a sort of vibrating sensation, like there are noisy buzz clippers nearby - problem?

No, you're fine! More than fine in fact. OBEs are a form of energy work, just like tai chi or qigong. Clock up enough energy work and you start to develop the chi flow that you're now feeling. Clock up more and (excuse the switch of cultures) your pranic awakening evolves towards a kundalini awakening. Personally audible crickets of no physical origin are one of the symptoms of kundalini activity - as are frequent OBEs. a href="http://groups.yahoo.com/group/Kundalini-Awakening-Systems-1/"http://groups.yahoo.com/group/Kundalini-…/a is an excellent bee-and-OBE-aware place to ask more questions if you want to.