Amazon Japan erased the information of the second DVD from the webpage.

According to Amazon Japan, the second DVD of Isshoni Training was announced to be released in February 2010. An art book of the DVD "Isshoni Training Hinako no Hon" will also be released on November 20th.

Cover of Hinako no Hon

Source: Amazon Japan

Updated on November 19th
According to Dengeki Online, the second volume will be released on February 11th, 2010 in both DVD and Blu-ray.

Source: Dengeki Online

Updated on January 1st
The official website of the second OVA "Isshoni Sleeping (Sleeping with Hinako)" was launched.

Isshoni Sleeping

They'll animate Hinako from going to bed till waking up and the OVA can be used for the assist of sleeping or wake-up alarm.