If you’re looking to promote an event beyond your personal Rolodex of contacts (do people still use these?), you’d be surprised at what’s at your disposal online.

Tap into your own community with a location-based social network like Brightkite.  This service lets you see what’s going on around you, whether it’s your personal friends or random local scenesters.

Brightkite is centered on a “What’s happening?” stream (a similar mechanism to Facebook’s status update), where people “check in” their current location, and if they choose, post a note or an image that relates to that “check in” status.  The stream shows you what your Brightkite friends are up to, as well as people in proximity to your location.  Changing the parameters in your “Around Me’ tab to your Region (100 KM), Metro area (50 KM), City (10KM), Neighborhood (2 KM), Block (200 M), or Close proximity (2 M) lets you decide how intimate you want those updates to be.   Brightkite also keeps tabs on mentions (when people name drop you in their posts) and comments to your own posts.

So let’s get down to business – savvy marketers and event coordinators can use Brightkite to update the community about their whereabouts, and by extension, promote their local event.   Posting a note and images along with the update is just icing on this free marketing cake. Let’s say I wanted to promote a Digital Marketing Meetup – coincidentally, there is one on March 19th, focusing on the Top 10 Search Engine Optimization Ideas.  Imagine that.  I can send out a location blast on Brightkite, include a note with all the details, and an image of the tasty Mellow Mushroom pizza and free beer (usually Heineken) we give away at every Meetup event.  Mmmmmm, beer.

The beauty with this service is I am able to reach a wider audience, because I am not restrained to my personal friends and connections.  Any Brightkite member who sets their “Around Me” parameters to include my location, will see the blast.