NealB-1's sandbox: Nice Phone Numbers

Provides formatted entry and output of phone numbers. Unlike the existing phone number field modules, this module is not a complete field. It provides an interactive entry widget, validation, and an output formatter that transform a basic text field into a phone number field.

Formatting and validation will be fully customizable without needing to write PHP code. Initially, it doesn't support international phone numbers, but it is not tied to any particular country. You can create your own patterns to match any country's phone number formats, and get interactive input formatting, output formatting, and validation. All three phases use the same patterns.