which mobile phone company to choose?

Hello everyone !!
I'll be soon in Japan, and I will have to buy a mobile phone because I will stay for a long time. I know there are 3 big mobile phones companies : NTT Comodo,Au and Softbank;
Which one to choose ? my criteria : being underdtood in english ( I(m a dumb in japanese !) the price !! the charges , the quality of the services if I've some difficulties with the phone ! the possibility to use my phone overseas ( in europe for example-ok maybe I'm dreaming ! lol)
Thank for your advice .

I'am a gaijin with a Softbank telephone that also works in Europe. Some models (or maybe many) can switch the menu betwwen japanese and english. Softbank has also an internet web-link in english which you can access with your phone. There you can find train connections (how to go from Chiba to Akihabara, or from Tokyo to Nagoya for example) which I find very usefull. You can aslo check the wheather if you want.

has all of those features (except being able to use your phone at home with a different provider) but for cheaper. And they won't rip you off if you buy a new phone for 0 or 1 yen. Softbank has been known to bill people for these phones later so their bill is actually much higher than it should be. Softbank is also expensive to cancel (which you might need to do when you go home). AU costs about 10,000 to cancel and Softbank is 50,000 yen.
AU's "daredemo" plan let's you cut your bills in half for a starting rate of 3000 yen. They also let you add three people that have ANY provider where you talk to and email for cheap.

If you're a long-time stay visitor to Japan, I really suggest AU.

here's some info:
http://www.au.kddi.com/english/

I started with Softbank and switched to AU because Softbank's service was lousy. They've tried hard to improve lately and have captured far more of the market but I am totally happy with AU service. I got the international phone and have used it in Hong Kong, Thailand and the U.S. with no problem whatsoever. I admit I have used it only for short calls overseas, but it hasn't been expensive at all.

AU costs about 10,000 to cancel and Softbank is 50,000 yen.

Just to clarify, au's "daredemo" service costs 10000 yen to cancel before 2 years. But that only applies if you already have phone service with them and switch to the "daredemo" plan. If you choose the "full support" plan which subsidizes your phone then you have a different cancellation policy. It's starts around 30000 yen and decreases by how long you have held your plan and finally disappears after 2 years.

Btw, I have au and have been more than happy with it for the last 4 years.

See more info here about mobile phones in Japan:

http://www.japan-guide.com/e/e2223.html

A few more things. The top 3 mobile phone companies are known for different things:

Docomo - coolest phones (depending on what you like), most expensive service, many overseas capable models

au - cheapest service, student discounts, possibly best coverage (some say Docomo is the best, it depends where you are), not many overseas models

Softbank - changes company name every few years, english customer service and support, all phones have english interface (although that seems true for all carriers now)

They all have confusing contract systems. Make sure you know exactly what you are getting into before you sign. They also all have pretty steep cancellation charges and phone subsidy charges if you cancel within 2 years.