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, two of the most popular sources are Handango, the leading online store for wireless applications, and eReader.com (owned by Handango competitor Motricity), the bestselling source for eBooks. These two destinations compile monthly statistics to chart what mobile users are doing with their devices.

In Handango's October chart, the Yardstick, for the first time two software developers and their applications made the best-seller's lists across three different mobile platforms each. MobiMate and Makayama are the creators of the WorldMate series and the various editions of DVD to Mobile, respectively. Their applications were best sellers in the Symbian OS, Palm OS, BlackBerry and Windows Mobile categories.

The best-selling fiction eBook in eReader.com's monthly chart is Dan Brown's The Da Vinci Code , while The Templar Revelation took the honors in the nonfiction category.

Java

1. Panda Mania
2. Labyrinth
3. Cave In!
4. EXOR
5. Solitaire
6. LangToLang English Spanish
Dictionary
7. Norbsoft nCard
8. Mobile Checkbook
9. Cocktail Mixer
10. Cuddles Mobile Java Pet

Symbian OS

1. eZiTap FEP
2. Quickoffice Premier
3. WorldMate Standard Edition
4. WorldMate Professional Edition
5. WebViewer
6. Handy Day
7. DVD to Mobile
8. DateMate
9. Remote
10. SKY FORCE

Palm OS

1. WorldMate Standard Edition
2. Agendus Professional Edition
3. AOL
4. CLOCK
5. Diet & Exercise Assistant
6. Backgammon
7. SplashID
8. Agendus Standard Edition
9. Aces Texas Hold'em - No
Limit 10. WebSphere Micro Environment

Windows Mobile-based Smartphone

1. DVD to Smartphone
2. SmartphoneNotes
3. ClearVue Suite
4. Pocket Streets
5. Power Calendar
6. eWallet
7. Power Tasks
8. SoundZ Cool
9. Photo Contacts
10. Jeyo Mobile Companion

Windows Mobile-based Pocket PC
1. PDA Contact
2. Spb Pocket Plus
3. Pocket Informant
4. Agenda Fusion
5. DVD to Pocket PC
6. Battery Pack Pro
7. PhatPad
8. PocketBreeze
9. Journal Bar
10. Microsoft Voice Command

BlackBerry

1. WebViewer
2. Aces Texas Hold'em - No Limit
3. Reqwireless Value Bundle
4. Sol Mania
5. MyFlashlight
6. EmailViewer
7. ImageWallet
8. PocketMac
9. ExpenseLog Pro
10. WorldMate