I'm reposting up here now that these actions are updated. The following link contains two actions: gvDialer and SMSgv action, which send phone numbers (either entered manually in the text entry field, or from the address book) to Google Voice, and dial a phone call or send a text message, respectively.
There's also a Snow Leopard Service of the gvDialer (great for using with Address Book. Just right click and dial...) Requires Growl http://www.zshare.net/download/65973283d3043733/
