Goodcopy allows a user to perform a plagiarism check by uploading a document (e.g. .txt, .htm, .html, .pdf, .doc, .docx, .ppt), scan a URL, and copy & paste text into a text scanner. It will output the results to a webpage plus the user has the option to download an exact copy of the results in PDF format.
Register at http://goodtogo.cc/wp-login.php?action=registerand sign-up for a free account. All new users are given 6 credits to try the plagiarism checker.