Mac2SMS is an application which uses FullOnSMS gateway to send SMS to any mobile in India.
It supports Google Contacts Sync so you can you just select whom you want to send a SMS from the apps Address Book.
This app features Automatic Message Spilt function, once you cross the 160 characters limit it will automatically split the message and send the SMS.
Comes with Batch SMS sending, allows you to send an SMS to any number of people. Separate the number using ','(comma).