Slydial allows you to leave someone a message on his/hercell phone without talking directly to him. Just call 267-sly-dial (267-759-3425), listen to an ad and enter the cell-phone number you want to call.
You will be automatically connected to the person's voice mail. Slydial's phone number is a Pennsylvania number, so you will be charged for a call to Pennsylvania. If you would rather not listen to an ad, you can pay $4.95 a month, or $29.95 a year, for premium service.