For those looking for a reliable online Greek New Testament, The Resurgence Greek Project is one of the best on-line electronic Greek New Testament sites that I have found.
Formerly http://www.zhubert.com, The Resurgence Greek Project provides a searchable Nestle-Aland 26 Greek New Testament. It also features parsing and word definitions by simply scrolling your mouse over the words. In addition you can access further data by clicking on a given word (e.g., word statistics, links to lexicons like Liddell-Scott and more.
The site allows the user to perform Greek and English word searches and more as well as making available several English translations (NASB, KJV, ESV, NET).