Smartphones like Droid and the iPhone have come a long way and have made screens bigger and more vivid than they were just a few years ago. However, despite this size increase, it's still small when compared to a laptop or even a tablet like the iPad, or Kindle.
A website not optimized for the smaller screens will look awkward and be very difficult to navigate and read. As a result you could lose a lot of potential supporters to your cause.
The best thing to do in this case is to create a mobile friendly site either in-house or by an outside party. Of course the price tag, or time investment may not be worth it. The good news is that you can create a template mobile site that looks good for about $20 a month.
The con of using a service like this is that you don't own the site - once you stop paying you lose the mobile website. Two, you lose customization, want to add social elements or plugins? Can't do it, they just take your current site and put in a mobile template. Three, if you continue to pay long enough, the cost will soon exceed the price of an outside vendor - so think in advance about going mobile, and the steps involved so that you can wrap your arms around the cost.
But for the short term, especially if you are entering a busy period, a service like bMobilized makes sense. If you go to their site you can preview what your site would look like if you used their service.