Hi Navneeth,

The approach provided by Saurabh is good. However it will fail at times as it is not bulkified and is not using the best design practices of Apex. I ahve reframed the same and following code should work for you. 

trigger LeadCreateAccount on Lead (Before Insert) {
	Public List<Account> lstAccts = new List<Account>();
	Public List<Account> lstNewAccts = new List<Account>();
	Public set<String> setLeadNames = new set<String>();
	Public set<String> setExistingAcctNames = new set<String>();
	public String name = '';

	// Create the set for al the names of the leads
	for(Lead l: trigger.new)
	{
		setLeadNames.add(l.firstname + ' ' + l.lastname);
	}

	// fetch the matching accounts if any exists
	lstAccts = [select id,name from account where name IN : setLeadNames];

	for(Account a: lstAccts)
	{
		setExistingAcctNames.add(a.name);
	}

	// Iterate through all leads to create acocunt if it does nto exists
	for(Lead l: trigger.new)
	{
		name = l.firstname + ' ' + l.lastname;
		if (! setExistingAcctNames.contains(name))
		{
			Account acct = new account();
			acct.name = name;
			// MAP ALL THE FIELDS U WANT TO MAP HERE
			lstNewAccts.add(acct);

			// Add this to avoid any duplication in current set fo leads
			setExistingAcctNames.add(name);
		}

	}

	if (lstNewAccts.size() > 0)
		insert lstNewAccts;
}

Regards