One of the first places people often turn to when searching for antivirus protection for their new computer is Symantec's Norton suite of security tools. The company is now looking to extend that protection beyond the PC to your mobile phone through its Norton Mobile Security app. This app, although currently in beta, adds an extra layer of protection to your phone well above just having a lock screen.
With the Norton Mobile Security application, you set up a secret passphrase and select "buddies" either from your phone book or by manually entering the number. Phone numbers on that buddy list can then send a text to your phone along with your passphrase to either lock down your phone, or in extreme cases, wipe both the phone memory and SD card. So if your phone were ever stolen, a simple text would render it useless to the would-be thief. Also available is an option to lock down your SIM card should the thief try to swap it out.
The app runs continuously in the background and can be scheduled to perform malware scans as desired. In addition, Norton scans each app that you download to make sure it will not harm your phone. The malware parameters can be updated manually or set on a schedule in the same way as the malware scans. You can also disable automatic updating when roaming, so you won't be hit with a huge data service bill.
Another feature I appreciate is the call and SMS blocker. You can choose to block someone from your call log, or (if you have a friend who keeps bothering you) someone from your phone book. The app can also suppress notifications: you can still see the text in the messaging app but you won't be notified of receiving it.
Even with the app running in the background, I experienced no slowdown or loss of battery life on my Motorola Droid. Despite its beta status, this app has the look and feel of a premium app, with no bugs (at least I could find none in three weeks of using it). The beta expires on the last day of 2010, when Norton Mobile Security becomes a subscription-based app (no word on pricing yet from Symantec). Be sure to download and try this excellent security app now while it's free.
You might also want to check out the similar, competing app WaveSecure, which offers a full-featured, seven-day free trial; an annual subscription is $20.