From their (newly revised) FAQ:
Can I run an online game via email, Skype, Google Hangout or a play-by-post forum?Well, woot! Who's looking for another player in their DnD Next playtest? I'm up for experiencing it from the other side of the screen, for once.
Yes, you may run online games via Skype, Google Hangout or play-by-post forum provided you to do not post or upload any transcripts from your playtest, upload any playtest materials and make sure that all members of your group have signed up to playtest through the official playtest sign up process.