american cell phones

can american cell phones be used in japan will they work

Almost all of the US cellphones don't work in Japan, and if they do, the roaming charges are expensive. You have 3 options:
1. Rent a Japanese phone
2. Buy an unlocked WCDMA phone and rent a Softbank SIM card (Y105/day).
3. Check with your carrier to see if they have agreements with Japanese carriers for roaming and if your phone is compatible.

all the services we use in america aren't in Japan. What you can do is sign up for an international plan so you can use it while you're there... though it depends on whether you travel there enough to get your money's worth.
I think you should look into it and see if your company has temporary international service that you can sign up for.

http://www.japan-guide.com/forum/quereadisplay.html?0+33535

In short, yes, if it has WCDMA 2100Mhz support for use in Japan, and you're carrier allows global roaming. Not 2100Mhz 3G USA bandwidth, but 2100Mhz 3G Japanese (most imports will be Japanese 2100Mhz ok; some USA AT&T 2100mhz phones won't work in Japan, only on USA 3G networks).

Almost all imports (eg. Nokia N95, 6233, etc) that have 3G 2100Mhz support will work in Japan.

AT&T current is the only carrier that has GSM phones with 3G Japanese support (only 2-3 phones I think) - check their international section.

No other provider has this with their regular phones - you'll have to rent/buy one from the instead. You can also choose to buy an import such as the Nokia 6233, N95, etc. that works for sure in Japan.