slydial
Ever have to call someone back who you really weren’t prepared to talk to? Slydial allows you to bypass their phone and go directly to their voicemail, leaving the onus on them to call you back. Brilliant.
I gave it a try and it worked, you’ve got to listen to a quick advertisement in the middle, but they did connect me direct to voicemail. Apparently you can either sign up as a member or pay 15 cents to skip it. From reading around a bit, it looks like this was possible in the past by going into your voicemail and choosing send, recording a message and then putting in the phone number. However, that usually only allowed you to send to people on the same network as you.