WiFi service in Japan

Since 3G data rental is ridiculously expensive (about 3000 JPY per 1MB) and roaming is as well (about 2000 JPY per 1MB) and so is unlimited rental (about 30000 JPY for 1 month) I need to find an alternative for having data access on the road.

Is there a such thing as a WiFi service that I can subscribe to, that will give me access in many places? For instance in other countries yo can sign up to a service and have access in any Starbucks or McDonalds (and more). This would be very helpful.

Thanks, as always, for your help!

Yes, McDonald's in Japan have yahooBB wireless which is a pay service. I believe its around 500 yen per day and you need to sign up for an account. Various coffee shops and hotels offer internet as well. Also check out freespot (http://www.freespot.com) which lists some OPEN wireless networks around the country. Note that the ones listed on freespot are generally NOT COST FREE as discussed here:

http://www.japan-guide.com/forum/quereadisplay.html?0+60298

yes,
most of the information is in Japanese only but:

NTT FLETSPOT
NTT MZONE
HOTSPOT
BBMobilePoint
Livedoor wireless

http://ja.wikipedia.org/wiki/%E5%85%AC%E8%A1%86%E7%84%A1%E7%B7%9ALAN

A quick translation:
Starbucks: Flet's Spot and MZONE

McDonalds: BBMobilePoint

Subway Stations: Flet's Spot, MZONE, HOTSPOT

JR East/West Train Stations: BBMobilePoint

Onboard trains only the Shinkansen (N700 only Nozomi) and new (not old) Narita Express Trains: BBMobilePoint

Though I think you need to be a resident of Japan to sign up for many of these services.
http://www.hotspot.ne.jp/en/signup/signup.html

HOTSPOT does offer a one day passport for 500yen if you can't sign up for any of the above, but still need access on the go.

Also check out this temporary free service offered by google through february 2010:

http://www.japanprobe.com/2009/12/01/google-offers-free-internet-at-ca...