A: The transfer of LLC member interests are done via written agreements signed by all parties. They are internal to the company and not recorded anywhere. You don't need to be in the US to accomplish the transfer. Depending on how the transfer is done, there shouldn't be any tax implications.
A: You need to file it with the county recorder or registrar and pay the recording fees. You can take it in to the county to file (if the desk is open . . call ahead) or give it to a title company to record (and pay their service fee).