IIRC, with Suckgular, we signed a contract December 22, 2004 and it lasted until 11:59 PM on Dec. 22, 2006. The 23rd, we switched out and had no problems. I can't say what it is with Verizon though, I recommend calling them to get a definite answer.
And, AFAIK, Verizon does in fact prorate their ETFs, so if you wanted to get out now, your ETF might only be a few bucks with less than a month to go.