Following up on the runaway success of the Pocket Wifi D25HW mobile router, EMobile has just announced a new device,the Pocket Wifi S.

Dubbed “S” for Simple and Smart, the new Pocket Wifi is not just a portable wireless router, but is also a fully functional smartphone running Android 2.2.

The Pocket Wifi S, or S31HW, seems to be a pretty pedestrian Android device with a 2.9 inch touchscreen, 512MB memory with a microSD memory slot.

What makes it interesting is that it will be able to share its HSPA 7.2Mbps down/5.8Mbps up connection wirelessly with up to five devices.  While docomo introduced this function about a year ago, the tethering speed was limited to paltry PHS speeds and data was only provided on a pricey PC plan.  EMobile is offering unlimited data on the phone, plus anything tethered to it for the low monthly cost of 4,280 yen.  To top it off, the Pocket Wifi S will retail for 19, 800! That’s about half of the cost of the last generation D25HW Pocket Wifi.

The Pocket wifi will be available in Japan in January of 2011 in three colors .

Press release (Japanese)