bulk voicemail

Hey guys. are there any apps, online services etc that allow you to do voicemail drops for free? Don't even need a service, just a way to do it manually would help already!

This might be beyond the scope of most folks here.. I'm trying to figure the commands to send a voice msg direct to a cell or voip phone ( without ringing it) I know there are services out there, but I want to be able to command line it or use a post command or something like that.. Any one...