Depends on your community, I'm small town so I use the local radio station..split 50/50 between paying them and them eating here. Website - got to have one, cheap to free (Microsoft Live small business). We do a birthday club from which we've built up pretty good data base, from which we do a monthly e mailing, and a quarterly newsletter. If you do a websearch you can find some pretty good information about how to do a newsletter (
Extra! Extra! Read All About It! Make Headlines With Customer Newsletters (Restaurants USA, January 1996) | Restaurants USA | National Restaurant Association Business Tools: 10 Tips for Creating an Effective Restaurant Newsletter On StarChefs). Tried cable, my staff loved it, cost a bunch and had to the best of my ability to determine, no sales.
Since I assume the Moderator read these, just a suggestion - as there is ton's of information on the web, maybe you could set up a forum for people to share bookmarked sites. I can guarantee everyone reading this has some saved that would be relevant.
When it comes to the day to day specials and new menu items - wait staff, they're the ones who sell it when all is said and done.