Try with Dejavu on the following link:http://dejavu.vbi.vt.edu/dejavu/

but it can only compare similarity between abstracts.

Thanks I'll try it

You can see the next link https://sites.google.com/site/realizartrabajos/plagio/detectar-el-plagio

Try viper, I would say its pretty good..

Thann you fellow researchers

Yes it is and it is essential for editors, reviewers and authors as well even to avoid one own words, please, see

http://www.dustball.com/cs/plagiarism.checker/

Http://plagiarism-detect.com/

http://www.plagium.com/

In the University setting, Blackboard has it.

Thank U All for useful links

Thank u all........... its so nice to see so many useful links at a go