Looking for a Book

[WordFloe]

Hopefully this is the right forum for this question. I am looking for a book I heard about once, probably 12 or more years ago. I can't remember the title of it so I am hoping that someone might be able to help me out, even though my memory is a bit vague.

It's definitely (probably) in the sci-fi genre, and the only main plot point I remember is it is about a group of people who make phone calls to themselves, which they will listen to at some point in the distant future when they reach a different planet. I don't remember why they are leaving their current environment, but I do remember it involved these phone calls.
It may also be that there will be very few survivors who make it to the new place, so perhaps the calls are meant as a sort of time capsule for the people to learn about their past...I kow it's pretty vague.

I appreciate any help or direction that can be given. I keep thinking it's a Bradbury book, but I tried searching for the plot in a search engine and nothing came up.