How to integrate the .Net application with LS Retail/ Navision 5.0 to send a SMS to customers

hi ,

I am a navision beginner.

I am using Navision 5.0 with LS retail .

I have to send a SMS through Mobile to the customers in navision.

For that i created a .net application and i need to integrate that with the navision.

So i need to know how to integrate .what kind of coding is required.

And also if you have better idea for sending SMS .Pleas let me know experts[:’(].