You can listen to police scanners on a laptop through the website Broadcastify.com. There are also other scanners that you can listen to on the website, including those for rail, aircraft, public safety and marines. There are also other ways to listen to scanners, and I'll highlight them below for ease:
If you have an android phone, you can download an app called FREE Police Radio Scanner that allows you to listen to police scanners from a variety of places.
Locations of police scanners include the USA, UK, Canada, Germany, Austria, Italy, Chile, and also Japan.
iPhone apps
There are also a number of iPhone apps available that allow you to listen to police scanners. I'd recommend Police Scanner + Free, which allows you to listen to scanners relating to all public services.