Wifi in Japan

Going to Japan for a week (vacation) are there wifi hotspots available for free? What options do I have?

Have a look at this page:

http://www.japan-guide.com/e/e2279.html

I've found the Starbucks free wifi very convenient, as the shops are everywhere. I'm currently staying in Japan without a mobile so whenever I pass a Starbucks I check my mail outside the shop. ;) Register here in advance, it's very easy, just insert an email address and comeup with a password.

http://starbucks.wi2.co.jp/sp/sma_index_en.html

Starbucks' free wifi used to be only in Tokyo. Have they expanded?

Well, I'm staying in a small city far from Tokyo and my nearest Starbucks offers it, also used it when I was in Kyoto last week in several shops. So I think it's quite common.

McDonalds used to have free wifi when I visited 2 years ago.

Starbucks' free wifi used to be only in Tokyo. Have they expanded?

Yes, quite dramatically in fact, and its now available pretty much nationwide:

http://300.wi2.co.jp/area/2/sbj_area/

McDonalds used to have free wifi when I visited 2 years ago.

Most McDonalds only offer paid wifi services provided by YahooBB mobilepoint.

Probably the most ubiquitous are the 7spot free wifi spots available at most 7-11 convenience stores around Japan.

http://www.sej.co.jp/services/7spot/top.html

Pocket WiFi rental
It's cheap and convenient

http://www.pupuru.com/en/service/emobile/

Starbucks is a good option; make sure you pre-register.
I had trouble connecting there once. I went into settings and "forget network" it was then able to reconnect.

JR East is expanding coverage at their stations. I've used JR East free wifi at Okachimachi, Shinjuku, and Tokyo. Tokyo & Okachimachi I had no trouble using video VoIP. At Shinjuku I have never been able to get a voice or video connection. (I haven't spent a long time trying though - it could be I have tried in weak signal spots or at crowded times of day.)