Just got a question from Alok in India. He wanted to build a system for sending sms messages confirming parcels sent to his customers. Thought this would be something quite useful for others also.

There are several ways of doing this.

The simplest way is to do it semi-manually using the Skype URI syntax. A link such as this works:

skype:+46739206106?sms

That kind of link works for anyone with Skype (and Skype Credits). Nothing needs to be installed, no authentication etc. However, that actually doesn't send the message, it just opens up a sms window with the phone number filled in. Can be useful but if you want to go a few steps further you need to automate Skype using the Skype API. First you need to reference the Skype COM API in C# as seen here:

Next step is to add a few controls to the form:

Then you would write some code like the following (in C#):

...
public partial class Form1 : Form
{
  private SKYPE4COMLib.SkypeClass objSkype = new SKYPE4COMLib.SkypeClass(); 
  public Form1()
     {
        InitializeComponent();
      }

    private void button1_Click(object sender, EventArgs e)
      {
      objSkype.SendSms(txtPhoneNumber.Text, txtSMSText.Text , "+46739206106");
      }
}

The above code sends the message in the txtSMSText textbox. No dialogs - the message just gets sent. From code you also get a verification that the message was actually sent successfully. Note that the third parameter, the ReplyToNumber only works for numbers that are already validated. The validation is done by going into Tools-Options-SMS in Skype:
 
Of course, the above simply gives you a replacement for the Skype Send SMS dialog but of course you could automate sending sms messages from your order entry system, crm system etc ...

Hope that gives you some ideas for how you can use sms in your development