partner-contact/crm_lead_formatted_phone/crm_lead_formatted_phone.xml

<?xml version="1.0" encoding="utf-8"?>
<openerp>
    <data>

        <record model="ir.ui.view" id="crm_lead_formatted_phone_form">
            <field name="name">crm.lead.formatted.phone.form</field>
            <field name="model">crm.lead</field>
            <field name="inherit_id" ref="crm.crm_case_form_view_leads"/>
            <field name="type">form</field>
            <field name="arch" type="xml">
                <data>

                    <xpath expr="//notebook/page[@string='Lead']/group/field[@name='phone']"
                           position="replace">
                        <field name="phone" on_change="on_change_phone('phone', phone, country_id)"/>
                    </xpath>

                    <xpath expr="//notebook/page[@string='Lead']/group/field[@name='mobile']"
                           position="replace">
                        <field name="mobile" on_change="on_change_phone('mobile', mobile, country_id)"/>
                    </xpath>

                    <xpath expr="//notebook/page[@string='Lead']/group/field[@name='fax']"
                           position="replace">
                        <field name="fax" on_change="on_change_phone('fax', fax, country_id)"/>
                    </xpath>

                </data>
            </field>
        </record>

    </data>
</openerp>