Retro Handsets for your cellphone

Sam writes - "As promised to all of you we ran into at the Maker Faire, here are instructions on making your own retro handsets for your cellphone. I apologize for the delay in posting - but one of you friendly Makers out in San Francisco was kind enough to share the black plague with me and I have been on the edge of death this week. I will cover bluetooth in this article, and will post about wired handsets a little later." - Link.