While there are differences from program to program, most include these basic features:

• Anti-Malware: Scans for infections on your phone and checks the safety of any new apps before you install them.
• Lost or Stolen Device Access: Using another mobile phone or a website, you can have your missing phone send information about its location, based on the built-in GPS or its location relative to cellphone towers. If you can't retrieve the device, you can remotely lock it, or wipe all the information from its memory.

Additional features are often included, such as:

• Anti-Spam: You can block incoming text messages and/or phone calls from specified numbers. This may be in the form of a blacklist (banned numbers), a whitelist (acceptable numbers) or both. Since many people pay individually for text messages, and we all use up airtime for incoming calls, this can be a handy feature.
• Site Safety Check: This feature checks to see if a site you're about to visit with your mobile Web browser will try to install malicious software or phish for personal information.
• Backup: Some programs include the ability to back up the data from your phone to an online storage account. That way, if your phone is damaged or you have to wipe the data remotely after losing it, you'll still have your information.

Unfortunately, mainstream tech sites such as CNET and PCMag.com, which routinely test computer-based antivirus software, haven't tackled mobile software yet. An Austrian not-for-profit organization called AV-Comparatives is the best source I've found for objective, in-depth reviews of Android security software: you'll find their up-to-date report covering nine prominent contenders here. They don't pick a winner, but they explain the different features available in each program very clearly.

As for those using non-Android phones, Trend Micro Mobile Security programs are available for iPhone and Symbian OS phones, Kaspersky Mobile Security 9 has versions for BlackBerry, Android, Symbian OS and Nokia phones, and McAfee WaveSecure offers coverage for BlackBerry, Symbian OS and Windows Mobile. And the latest iPhone software has the ability to find and remotely wipe a lost or stolen phone built right in.

Next: Your best defense is still common sense. >>