Another possibility would be to use AddEmail. Their blurb says: Email ActiveX (COM) Control - create and send HTML email messages with embedded images and attachments using SMTP/ESMTP protocol. Easily add email support to your Visual Basic 6 (VB6), ASP, ASP.NET, VB.NET, C++, C#, FoxPro, Access, PowerBuilder or Delphi application.
We use it a lot to automate our software registration system, and it'd be no problem to splice it into a bit of Excel VBA,
....
Dim oSmtpMail As New SmtpMail
Dim lRes As Long
lRes = oSmtpMail.SimpleSendScriptable(sRecipient, sRecipient, sSubj, sText, sError)
....
Okay, so it's email rather than SMS, but it's a start.