My friend bought the i-phone and complained that it is very expensive. every month, he has to pay for 8,000 to 12,000 yen. This is because every thing is connect to internet, and that's why it is unavoidable not to use.
Iphone is good design phone, but if you will do lot of typing, e.g. word proccessing and stuff like that..it is not suitable and of course u cannot use it as a portable harddisk. Also, monthly cost is something very expensive. Recently, A dev team is able to unlock the phone, but be causion that..it is very difficult step and i myself have not tried it yet. here is the link http://blog.iphone-dev.org/post/67797811/dont-eat-yellowsn0w
more thing, you need to buy of lot application (althought it starts from 200 yen)..but in the end you will end up with lot of application to buy and game too.
for me, I already disconnected my phone and just use it ipod function and wireless.
anyway, if you need to know more just post on this web i will reply you more again.
thank you very much for your comment. my bf just bought it the day before, omg it is such uncomfortable little hand holding big mobile phone. but sound from MP3 player is very nice hehheehe. thanks anyway