Nokia Pulse has snuck into the Windows Phone Marketplace. It's a beta version so you still may see some bugs and you may not find it with a keyword search, but it's there.
Pulse is a social app to help you keep track with friends and family and let them keep track of you. As the video describes, Pulse is about where you are, where you're going, what's around, and what do you want to do.
The app does require registration to Nokia Services (free) and allows you to create groups from your contacts. From there you can text, map locations, and share photos privately among group members. Nokia Pulse also supports push notifications and is accessible from your desktop/laptop via the web.
Nokia Pulse is a free app but remember it's a beta right now. You may encounter bugs, glitches and other oddities. It is nice to see Nokia open up their apps to other Windows Phones and hopefully this is a good sign that we may see other Nokia apps headed to the open Marketplace (Drive maybe?).
If you're curious and want to take Nokia Pulse out for a test drive, you can find it here at the Windows Phone Marketplace.
Thanks goes out to Laseven for the tip!