First of all, keitai is short for keitaidenwa (携帯電話）or CELL PHONE. As you can imagine in a city of how-many-million people, keitai are NECESSARY for daily life.
I've been to the AU Shop (they sell cell phones, very popular with students b/c they give a discount) three times now. I still don't have a cell phone.
It takes a long time to process everything, so my host father (who's been helping me) and I returned to the shop yesterday to pick the phone up. However, the lady comes out and bows deeply (and that's when you know something's up).
You are a minor until age 20 (hatachi) in Japan, and being 19 means you need a parent signature to get a phone. So I have to return tomorrow (my birthday) to get the phone [rolls eyes]. But the story gets more complicated, I assure you.
See, all the other exchange students are getting keitai as well, but we all hear different stories. "you can't get it if you are leaving in July" "you must pay $60 cancellation fee" "two-year contract only" "one year contract okay" "you must pay $30 cancellation fee" "the phone is free" "the phone is not free" and on and on and on. So I am a bit apprehensive about the contract-- I wonder if they will change the fee schedule on me... I will have to ask many questions tomorrow!
INTERESTING KEITAI DETAILS:
They have "IR": you can point the cell phones at each other and transmit your contact information.
They have some sort of barcode scanner- the club posters have a small square printed on them that you can scan with your phone that automatically "dials" the URL of the club's website into the phone, and presto! you arrive at their webpage without having to type the URL address.
Everyone (including my host father) has a cell phone ornament! Some people's ornatments are bigger than their phones! The cell phones have a little slot to attach the ornaments.