Are you one of the lucky 6.7 million Americans who got a GPS personal navigation device at the end of last year? A whopping 47% of those units were made by Garmin, the U.S. market leader (TomTom is in second place with 21%). If you have a Garmin StreetPilot or Nüvi, we’re going to show you how to pump up that already-indispensable technology, making it even more useful with software enhancements, new maps, and also a crucial accessory that every Garmin owner should have. Best of all, most of these enhancements can be found for free.

Let’s start with the simple stuff. Are you still sticking that GPS unit on your windshield with a suction cup? Yeah, I tried that for a while, and it was constantly falling off and into my lap while I was driving — a definite distraction if not a downright dangerous nuisance. It also blocks your view, especially if you have one of the widescreen units.

Here’s the crucial accessory: Forget suction cups and get a Garmin Portable Friction Dashboard Mount (pictured above, around $29), which miraculously holds your Garmin in place on the dash, no matter what you do. Believe me, I tested its mettle by driving rambunctiously to the point of recklessness, trying to shake the friction-mounted unit off the dash. It just wouldn’t budge. It’s as secure as if it were nailed down (well, unless you roll your car), and puts the unit’s screen just below your line of sight out the windshield, not obstructing anything and plainly visible. This baby is a must-have.

Now let’s make sure your maps are as up-to-date as possible. First, go to Garmin’s website and make sure your unit's software is up to date. Sometimes these updates speed up important things like satellite acquisition, so it’s a good idea to download the latest version, upgrading your device by simply connecting it to your computer via the USB port and clicking on the downloaded software. After that’s done, see if there are map updates available on that same site.

After a quick entry of my Garmin’s serial number, I discovered I could get a free update to my StreetPilot C550’s maps after entering a secret number from the product box’s documentation. Unfortunately, the software will be delivered to me on DVD via old-fashioned snail mail, but that’s the only way to get it. See if you’re eligible, but if you’ve already tapped out your free map updates, the latest version, the 2008 City Navigator for North America NT, is $50. Helpful hint: Garmin’s newest North America 2009 Map Update will be available in April (2008), so it might pay to wait a month for this.

Once you have your maps updated, let’s get more free stuff. There’s a growing community of Garmin users who are offering up huge databases of points of interest (POI) that you can download (for free). These POIs can guide you to all your fave restaurants, hotels, parks, night life, whatever — even lighthouses. For example, if you want to know where every Starbucks café in North America is located, you can download a file that will place that data in your GPS system, showing little Starbucks icons for every café. For Garmin systems, you must first download a small application called Garmin POI Loader, and then you’re off and running.

I’m a fan of Culver’s restaurants, so I found a POI database that shows where every one of those luscious custard stands is located. Yum yum. Many of these files are offered for a fee, but don’t pay for them. Try my favorite site, POI Factory, (registration required, but the files are free) where nearly any interest you have is represented by easily-downloaded POI files. The data works on Garmin, Magellan and TomTom systems, too.

Next, let’s install a bit of kookiness into your Garmin with a huge selection of free indicator icons. You can change that boring icon that looks like a car or arrow (highlighted in the graphic at right) to whatever conveyance that suits your fancy. There are so many to choose from, you might be able to closely match that car or truck you’re driving, or replace it with an ambulance, fire truck, or tank. Get crazy with Maposaurus, a paper airplane made of a folded-up map (no doubt mocking that old-timey mode of navigation), or even choose the Black Pearl ship from Pirates of the Caribbean in either right-side-up or upside-down mode. Your kids might think you’re crazy, but some of us rather enjoy being led cross-country by a rocket sleigh.

On a final note, if you don’t have a GPS unit yet, there are some selling for a little as $80, but if you must have a Garmin, we saw this widescreen Nüvi 200W on sale for just under $200. Great deal.