Like a desktop computer, you can't do much with PDA or smartphone, beyond the basics, without third-party software. As a result, a lucrative market has developed around the application needs of mobile users. Although there are a number of ways to purchase mobile software, one of the most used sources is retailer Handango.

In Handango's November Yardstick of the most popular applications and the devices they are downloaded to, a new handset took the lead as the number one phone adding mobile content. The palmOne Treo 600 topped the list for the first time in its history, indicating a big appetite for applications from customers of the popular device. The company's Tungsten T series lead for PDAs.

Searches remained relatively consistent with MP3/Music, GPS and Games totaling approximately 12 percent of the top searches. Ringtones and Internet rounded out the top five accounting for more than 6 percent of the searches.

Close to 50 percent of Handango's sales came from the personal productivity plus business & professional software categories with entertainment a distant third at 14 percent.

Go to the next page to see the ten best-selling applications by operating system.