phone number regulr expression

Use this
^(0{1,2}|\+)(\d)+$
You can specify count of digits too if you wish.
^(0{1,2}|\+)(\d){10}$

see
Validation

try this one too :
^([0]{1,2}|\+)[1-9]\d{7,10}$

7 = minimum number of digits after first nonzero gigit
10 = maximum number of digits after first nonzero gigit

To validate Text Filed for valid PhoneNumber using Vb.Net
Set the Maximum length for Textbox Control equal to 15.

Public Sub ValidPhoneNumber(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs)
        Select Case Asc(e.KeyChar) 'Validating PhoneNumber using Ascii
            Case 8, 45, 43, 48 To 57  'if Ascii is 48...57 then allow
                e.Handled = False
            Case Else                 'Else Providing Message 
                e.Handled = True
                MessageBox.Show("Please Enter Number's Only", "Warning", MessageBoxButtons.OK, MessageBoxIcon.Information)
        End Select
    End Sub

Call the above method on Texbox KeyPress Event.
It allows following types of Phone Numbers
022-2123456
91-0123456789
+91-012345678
0123456789