Language Transfer at languagetransfer.org is the best free resource I know of for learning Greek.

Here are some helpful facebook pages > 

https://www.facebook.com/SkypeGreekatHome

https://www.facebook.com/babel.edu

and sites >

http://www.greekpod101.com/ ;

http://www.hau.gr/?i=learning.en.greek-podcasts

Jessica, thank you. Sites are interesting.
Bruce, thank you. I mean Modern Greek, but Classical (Koine) are interesting too!

 Hi Dimitry:

   Is your interest in Classical Greek or Modern Greek?

1. Communicate in Greek (Επικοινωνήστε Ελληνικά) The complete course would be three books, each for levels 1-3.
2. The interesting list of links http://www.italki.com/discussion/74643