how to change admin url in magento?

Step1:- Go To root folder than
app/etc/local.xml 
open local.xml file and change below "CDATA[admin]" code.

 <admin>
        <routers>
            <adminhtml>
                <args>
                    <frontName><![CDATA[admin]]></frontName>
                </args>
            </adminhtml>
        </routers>
    </admin>
NOTE:- use only small character.

Step2:- go to var/ folder and delete cache folder.  Now open admin with you're new admin name url..