Fire Eagle is a service from Yahoo! which lets you share your location between different applications. whereyougonnabe can automatically update your location in Fire Eagle based on the plans you've told us about. Other applications can query Fire Eagle for your current location, if you authorized them to do so.
You need a Yahoo account to use Fire Eagle. Assuming you have one, to set up Fire Eagle integration you just click on Settings in whereyougonnabe, then click on the Other Systems tab and scroll down to the Fire Eagle section:
Then just click on the button which will open the Fire Eagle site in a separate browser window, and you just follow the instructions to authorize whereyougonnabe to update your location. You can remove this authorization at any time at the Fire Eagle site.