For better or worse (and it is worse in my opinion) they have moved this feature...at least in part...to the Messages app.
While looking at a "conversation" in the Messages app, click "Details" in the upper righthand corner. Click "Share My Location" to share you location with members of the conversation. Your options are "Share for One Hour," "Share Until End of Day," or "Share Indefinitely."
No one else in my family has upgraded their phone to iOS 8. I am under the impression it only works with other people using iOS 8, but I haven't gotten it to work with anyone, yet.
Tom
iPhone 5, iOS 8.1