Since 2006, when Wi-Fi information and services firm JiWire proclaimed Wi-Fi hotspots had topped the 100,000 mark globally, the list of hotspot locations has continued heading skyward. As of March, JiWire reports there were nearly 250,000 free and for-pay hotspot locations in 136 countries. (That number isn’t 100% all inclusive, but JiWire’s registry is likely the most comprehensive available.)

The good news for U.S. travelers is that more than a quarter of those hotspot locations are located stateside. Nevertheless, coverage is far from ubiquitous, even in densely populated urban areas where hotspots are most common. For example, Portland, Ore., the No. 1 hotspot city per capita, according to the Forbes 2008 America’s Most Wired Cities report, boasts only six hotspots per square mile, on average.

Factor in the realities that many hotspots have a range of 300 feet or less and that hotspots cluster where people congregate, and the picture turns into a surrealist landscape. Without advanced planning or the right tools, you can easily find yourself stranded in a Wi-Fi desert. The nearest Wi-Fi oasis might be only 1,000 feet away, but you’ll never know it’s there.

How can you prevent the grim scenario depicted above? One possibility is JiWire’s Wi-Fi Hotspot Helper for Windows XP. The device locates nearby Wi-Fi access points by cross-referencing your location against a database, stored offline on your PC, of more than 200,000 verified hotspots. Bonus features are a Wi-Fi mailer, which moves email through blocked hotspots, and enterprise-grade encryption and firewall security. The trial is free, but Vista users are out of luck. If you are a Skype or iPhone user, JiWire also offers a free finder utility without the security and email perks.

If you would rather map out hotspot locations before you leave home, or before leaving your last hotspot, JiWire’s searchable online database can assist. Other sites such as WiFinder, a good place for state-by-state searches; Wi-Fi Free Spot or Open WiFi Spots, each of which are great Web sites for dree Wi-Fi locations. Open WiFi Spots offers category guides, such as restaurants, public parks, and municipalities, and interactive mapping of Wi-Fi locations to get you going.

Several major restaurant and retail chains, including McDonald’s, Borders Books, and Barnes & Noble, offer fee-based Wi-Fi. At Panera Bread and hundreds of other cafés and fast-food restaurants, Wi-Fi is free. At Starbucks, a $5 Starbucks Card will soon give you two free hours per day of Internet usage. Companies such as Wayport and Boingo, which often power the Wi-Fi at hotels, restaurants, and retailers, offer prepaid cards or subscriptions that give you access at any of their locations.

To be continue tomorrow.