I suspect we'll see more winery blogs started this month as people act on their New Year's resolutions to market their wines more actively.
Do you love your wines? Do you have an interesting story to tell about them? Are you willing to make a weekly commitment to telling that story to people who are interested in hearing it? A blog for your winery might be the answer. I recommend starting quietly - when you publicly announce your blog, it's nice to have 5-10 "previous" posts, as it adds weight and shows that you're committed to writing.
Now that I've written that, I realize may have prematurely "outed" Chateau Julien's new blog (which I found because they mentioned The Winery Web Site Report, which showed up in my Technorati watch list (you have one set up for your winery's name, don't you? Think of it as a press clipping service, only for mentions of your winery in logs...)).