You have the site importer, with will be my last choice, and you get this one guide: http://dev.day.com/docs/en/cq/current/howto/website_quick.html
Hi matheus ,
i am worry if my website has 25000 pages then it would be very difficult for anyone to start from stracth.
such projects, where the content is not manually re-created in CQ, usually resort to coding a custom importer. we'd have to know more about the other system to advise on details. generally you'd code a OSGi component that connects to the other system (e.g. to its database, or its XML export, ...) and creates CQ pages and paragraphs from it, depending on a mapping configuration (map template of other system to CQ template, map content of other system to CQ components [paragraphs]).
there is no a magic way to import a thousands of page between some kind of CMS and CQ I think that it is not possible at this moment to use some standard tool.
The only way, like it was suggested by hypnotec is to create some custom migration tool for connecting to content resource, migrating content data, creating xml structure readable by CQ and then installing it in the CQ.
My team during last 4 months prepare this kind of tool, which connect and ready content, stored as a xml file in the NAS and then transform those xml files to the xml file structure used by CQ. But before implementing this kind of application you need to recreate at least a templates, components in the CQ, then having a structure of future application in the CQ you can to implement a tool which transform some content data from some system to CQ.