Expect a similar press release from Canon USA shortly... meanwhile, see these pages:

Press Release: (in Japanese) (http://cweb.canon.jp/newsrelease/2009-07/pr-hf21.html)
iVIS HF S11 page: (in Japanese) iVIS HF S11 (http://cweb.canon.jp/ivis/lineup/hivision/hfs11/index.html)
iVIS HF21 page: (in Japanese) iVIS HF21 (http://cweb.canon.jp/ivis/lineup/hivision/hf21/index.html)

and the English translations via Google:

Press Release: Google Translate (http://translate.google.co.uk/translate?hl=en&sl=ja&tl=en&u=http%3A%2F%2Fcweb.canon.jp%2Fnewsrelease%2F2009-07%2Fpr-hf21.html)
iVIS HF S11 page: Google Translate (http://72.14.247.132/translate_c?hl=en&sl=ja&tl=en&u=http://cweb.canon.jp/ivis/lineup/hivision/hfs11/index.html&rurl=translate.google.co.uk&usg=ALkJrhja9lxJrnZYyS3MdHhb9YxEYGQGxA)
iVIS HF21 page: Google Translate (http://72.14.247.132/translate_c?hl=en&sl=ja&tl=en&u=http://cweb.canon.jp/ivis/lineup/hivision/hf21/index.html&rurl=translate.google.co.uk&usg=ALkJrhjwEd4FvaZKRlRaozt0HBYKigLO1Q)

Also, Canon Japan has set up a mini-site for the HF S11: iVIS HF S11 SPECIAL SITE (http://cweb.canon.jp/ivis/hfs11-sp/index.html) and one for the HF21: iVIS HF21 SPECIAL SITE (http://cweb.canon.jp/ivis/hf21-sp/index.html)

iVIS is the family name for the models going to the Japanese market, just as VIXIA designates North America and Legria is for the Eurpean versions. The only changes going on here (as upgrades from the HF S10 and HF20) are the expansion to 64GB of on-board Flash RAM for video recording, and support for 64GB SDHC cards, for both of the new models. Additionally, the HF S11 has an improved Optical Image Stabilization mechanism and a new Night Scene shooting mode. The HF21 has no other changes though. More info forthcoming when the U.S. announcements appear.

In case anybody has missed it, Canon USA announced the VIXIA HF S11 today:

http://www.dvinfo.net/conf/digital-video-industry-news/296612-canon-usa-announces-vixia-hf-s11.html

...please post replies regarding the HF S11 to that thread.

What's interesting is that Canon USA did not announce the VIXIA HF21. They
will, however, sell this camcorder in the U.S. exclusively through Best Buy.

It seems to me that it only improve the build in capacity and the stabilisation (witch is good i guess) i was expecting few other new features... like a proper slow recording mode, like what does the camera Casio EXILIM Pro EX-F1. That's pretty good when you see some good tests :
New York 2008 on Vimeo (http://vimeo.com/2910103)

that was my hope for the new one...