Apple has updated its iCloud website, adding a section for Find My Friends. This lets iCloud users locate their friends on a desktop should they not be able to use their iOS devices. It's icon is on the second row, right next to the Find iPhone icon.
Find My Friends, which displays the location of your friends on a map, assuming they choose share it, has been around on iOS for some time now. It was even integrated into the system as part of iOS 9.