Hi Revathy,
THere are lot of options available
pls check
http://hameersaleem.blogspot.in/2011/03/if-your-users-are-naughty-enough-and.html
http://sharepoint.stackexchange.com/questions/62598/hide-create-new-subsite-in-sharepoint-site
http://social.technet.microsoft.com/Forums/sharepoint/en-US/54217f6a-ac82-44b6-a60d-298c55cdfef4/quick-way-to-prevent-users-from-creating-subsites-under-their-my-site?forum=sharepointadminprevious
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