changing phone numbers

I have two lists of about 5000 names and addresses each. The phone number column has numbers listed like this +1.xxx.xxx.xxxx for the first spreadsheet and the other spreadsheet is like this xxx.xxx.xxxx
I would like to change them both to xxx-xxx-xxxx
Anybody have an idea how I can make this change easily. I don't want to have to change each entry manually.

First sweep select everything- edit replace +1. by "" replace all
Second edit replace "." by "-" Replace all

Thanks, it worked like a charm.

Thx for the feedback