In what countries will the iPhone SE be available?

The iPhone SE launch on March 31, 2016 will take place in 12 markets:
Australia
Canada
China
France
Germany
Hong Kong
Japan
New Zealand
Puerto Rico
Singapore
United Kingdom
United States

The iPhone SE launch on March 31, 2016 will take place in 12 markets:
Australia
Canada
China
France
Germany
Hong Kong
Japan
New Zealand
Puerto Rico
Singapore
United Kingdom
United States

No, the iPhone SE camera is flush with the back of the phone.
Apple made headlines when the iPhone 6 was released, thanks to a protruding camera lens on the back of the device. The iPhone 6s also suffers from the camera bump, however this design accommodates the thinner profile of these larger phones.

The iPhone SE has a Nano SIM card (4FF).
Apple first utilized the Nano SIM form factor in the iPhone 5. Previously the iPhone 4 and iPhone 4s used a Micro SIM card.

Yes, the iPhone SE has HD Voice capability.
Whether or not the iPhone SE delivers full wideband audio during a phone call depends on a variety of factors. First off, the availability of HD Voice depends on what network technology is deployed by individual carriers. Even carriers that support HD Voice may have only rolled out support in particular markets.
Yes, the iPhone SE has the same 12-megapixel iSight camera as the iPhone 6s and 6s Plus. The iPhone 5s is only equipped with an 8MP iSight camera. The iPhone SE also includes most of Apple's latest camera technology, besides optical image stabilization. These features include 4k video, Focus Pixels, support for Live Photos and more.