Deepak Jain from MobileGyaan has compiled a real cool list that has more than 20 options for you to send free sms while you're in India. The list includes choices for sending free Individual sms, group free sms as well as International free sms.
The list includes favorites like Gupshup and IndiaRockz as well as hitherto unheard of sites. And while you're there don't forget to thank him =)
Have Fun ! And hold yourself from sms bombing somebody's phone !!