Selling advertising on customized Google Maps is becoming increasingly common, with agencies such as LAT49 showing the way. Ads have been sold on maps for hiking, jogging trails, local transit and other categories.

Now Wedding Mapper is taking the same concept to weddings, where it allows couples to map out a wedding trail of airports, receptions, hotels and rehearsal dinners. The free maps can be emailed, downloaded to mobile phones, printed out or posted on websites. Wedding Mapper, which grew out of Community Walk.com, a non-specific map builder, was launched in January 2007. It has already produced 100,000 maps, and is likely to climb further as it gets a bigger piece of the wedding market, which sees 2.2 million couples married every year, per The Wedding Report.

Founder Jared Cosulich tells us that the maps are configured on a hyper-local basis for 10,000 communities in the U.S. and abroad, and advertisers can target any of those communities, with the average spend roughly $20. About a thousand advertisers have tried the service out. He adds that the micro-targeting figures to be especially compelling for exurban and rural communities that are normally left out of wedding-related media (but I might question that: small town folk tend to know who vendors that they want to use).

Cosulich notes that one of the most compelling things about the service is that maps have quite a long tail. Here’s why: The five person, San Francisco-based crew have created a User Generated directory of 140,000 wedding vendors that can be used to pre-populate map locations. The directory is given extra context by adding user reviews from businesses that have been mapped. More than 50,000 reviews have been entered so far.

I built a couple of maps for fun, one for my current town (Carlsbad, CA) and one for my college town (Bronxville, NY). I found that they’re easy-to-launch, wisely password protected, and the categories are intuitive and well thought out. But the map experience is far from perfect. While the maps will surely get your guests around town, the User Generated directory is far from comprehensive. Users that rely on it would find reception locations, churches and bars and airports many towns and miles (and scrolls) away from optimum locations.

Trust me, when you’re getting married at The Crossings in Carlsbad, you probably don’t want to stay in Dana Point, 30 miles up I-5. There are dozens of hotels and resorts in between. But I bet that will get better when the site relaunches this Sunday.