Recuerda hacer los siguientes imports
Cita: Imports cpSphere.Mail.Pop
Imports cpSphere.Mail.Mime
Despues declaras 2 variables globales para hacer el pop3 y la interfaz:
Cita: Private thePop As Pop3
Private components As System.ComponentModel.IContainer
Ya en tu evento donde haces el llamado pondrías algo como ésto: (voy a ponerte un ejemplo que hice en modo console)
Cita: Sub Main()
components = New System.ComponentModel.Container
Console.WriteLine("Starting ..")
thePop = New Pop3(components)
thePop.Hostname = "el_servidor_de_correo"
Try
'Connect to server
Console.WriteLine(thePop.Connect().ToString)
'Login
Console.Write("User:")
thePop.Mailbox = Console.ReadLine
Console.WriteLine()
Console.Write("Password :")
thePop.Password = Console.ReadLine
thePop.Login()
'General Statistics are available, print them.
Console.WriteLine("There are {0} messages of combined size {1} bytes", _
thePop.
MessageCount, thePop.Size)
Catch ex As Exception
Console.WriteLine("ERROR = " & ex.Message)
Exit Sub
End Try
Dim
msg As cpSphere.Mail.Mime.Message
Dim intMsgCount As Int32 = thePop.
MessageCount 
...
...
End Sub
Salu2 y espero que te haya servido
