http://www.plagium.com/
There are several such checkers:
1. duplichecker
2. plagium
3. textbroker
4. articlechecker
5. plagiarisma
They are all free... Some better than others but on the whole, you can get excellent results.
I am sorry... I cannot post links
http://plagium.com
http://duplichecker.com/index.asp
http://www.copygator.com
http://www.dupefreepro.com
- similarity checker between versions of spun articles similar to functionality within spinnerchief
http://www.textbroker.com/uncover/
- highly customisable deplicate content checker that can run automated tasks as well as individual article checks
I'm aware of copyscpape, but is there a free or cheaper alternative that can compete with copyscape and check hundreds to thousands of pages or text files in bulk? I know copyscape isn't that expensive but I plan to check a very large amount of content
[URL]http://www.textbroker.com/uncover/[/URL]
- highly customisable duplicate content checker that can run
automated tasks as well as individual article checks