There are many site which provide free sms service for india. but most of them limit char to 120-140 and add a advertisement line.
Whozzat is a unique and first site which provide long and ad free sms for india.
some other feature:-
1. phonebook
2. send to many
3. support flash and hindi sms.
4. easy user interface
5. social network

link: www.whozzat.com
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