This most adorable "Nendoroid Puchi Hatsune Miku" will come with the 8th edition of Quarterly Pixiv - a illustration book which highlights the works of pixiv users. The "Quarterly pixiv vol.08" is due out on the 9th of March.
Folks who are interested in seeing their work in the book need to post any illustration of an original character and tag it "Qpixiv8フリー" - more details in Japanese at Pixiv.
The book is due to retail at 1,680 yen and just went up for pre-order at Amazon Japan.
Hopefully will be up for pre-order at one of the following online retailers too.

http://www.1999.co.jp/eng/
http://www.amiami.jp/shop/?set=english
http://hlj.com
http://archonia.com
http://kidnemo.fm
http://hobbystock.jp
http://jlist.com
http://www.toylet.net/

Photos from http://www.famitsu.com/news/201112/26007736.html