I was just introduced with an interesting SMS service offered by a Pakistani company. Some interesting features include:

• SMS for free on any number in Pakistan (it seems like a hoax but it’s not)
• All your sent and received messages are saved on your profile
• Personalized tagging for everyone you are having a conversation with
• Delivery status (you would know if your sent message has been delivered to the receiver or not)
• You can integrate your Twitter account with it as well
• Numbers of invitation increase as more friends accept to register
• Ideal for everyone who live outside Pakistan and want to stay in touch with friends

Site: iSMS.pk
Membership: Free (takes 1-2 days to process)