For anti-virus software?
Guess what: you may want to try...
Antivirus!
Lookout is also good anti-virus software. And it adds phone tracking (GPS) in case of loss or theft, and a remote 'scream' command (if you still can't find it at its GPS location). The paid version adds remote shut down and wipe.
Both apps are free and available from the Market.
I have both installed (double anti-virus scanning). They get updated often, primarily for new virus definitions of course.
I suggest you password-protect the Lookout app with an applocker to prevent uninstalling by a thief. Also free and available in the Market.
Also convenient to hide your porn collection...
Of course you can also track your phone by running Google's Latitude app, stock on your phone, and having it tracked by/on someone else's phone (like your wife's? Or would that be a recipe for divorce...
?)
Or you could run the free
WAZE app on your phone. If you don't disable it (it's on by default) other WAZErs see your phone's avatar on a map, with coordinates. So in case of loss or theft all you have to do is get hold of another phone and start up WAZE on it and bingo: you can see where your phone is on a dynamic map.
WAZE is a crowd-sourced LIVE satnav/routing/traffic information system. Ideal for people who drive a lot. Know at the same time as the cops do that a traffic jam is building because of an accident some distance ahead on your route. And you can decide, or not of course, to detour early and effectively.
OR you could of course run the FourSquare app. Same m.o.: look up on someone else's phone where yours is.
Etc., etc., etc.