I tried the Facebook recipe shared by someone else but it appears to be broken. This Twitter recipe I cooked up is tested and works great!
You'll need to set up your Google+ account to be able to send posts from SMS via Google Voice. Your Google+ account and Google Voice account need to be using the same email address I believe.
1. In your Google Voice settings on the Voicemail & Text tab, turn on text forwarding to email.
2. Save changes and send a new text via Google Voice to 3366...