SOS Nowforce is now online and you can register in either Hebrew or English.

SOS Nowforce is an app for your smartphone that lets you easily call for help if you are in trouble. This system has been set up in response to the kidnappings this past week.

From The Times of Israel article earlier this week (before registration was possible):

NowForce is well known in the emergency services community. The company’s apps are used by fire and rescue, EMS, campus security groups and law enforcement services around the world. In the US, for example, the app is used by fire officials in Boone County, Missouri, to keep track of emergencies in the 500 square mile area they are responsible for. The 250 volunteer firefighters, the only ones available in the area, carry the NowForce app on their mobile phones. The app immediately alerts volunteers in the area when a 911 emergency call comes in reporting a fire. With the app, response times in the mostly rural area are in the two to four minute range, far better than they were before the district started using the app, say fire officials.
The emergency app NowForce is offering Israelis includes a big SOS button, which app users press to set the process in motion. Once the button is pressed, the NowForce reporting center will alert responders who are in the area of an emergency, including police, local security officials and United Hatzalah emergency rescue workers. The app shows them a map of where the incident took place, and provides turn-by-turn instructions to get to the site. It also provides forms, updates and anything else connected to the specific incident, and lets responders take photos, videos and audio recordings of the incident.
The app will also simultaneously call the police and send the caller’s location to his/her emergency contacts and local emergency service providers such as United Hatzalah. “We invite the police and other national and local emergency service providers to take part in this initiative to safeguard Israel’s citizens,” she said.

It is definitely worth registering and installing this app on your smartphone, and on the smartphones of your children...