New Testament Greek
NTGreek.net
Registered students pay a $200 fee, but the good news is that you can go through the online course for free, just without help. Jeff Smelser is the minister of the Centreville church of Christ and has done a great job in putting the site together.
http://www.ntgreek.net/
Greek Bible Study
If you want an excellent parallel Bible with NT Greek then Greek Bible Study is superb. The only caveat is that you have to register, but that is so you can take notes and it’s all FREE!
http://www.greekbiblestudy.org
The New Testament Greek Lexicon
If you want a quick free and flexible lexicon, check out Crosswalk. You’ll find other tools linked from their site too!
http://www.biblestudytools.net/Lexicons/NewTestamentGreek/
Finally I’d like to give a tip of the hat to Duke University’s Dr. Mark Goodacre and his site The New Testament Gateway. Why should I list every great NT Greek site, when he’s got them?
http://ntgateway.com/