You've been battling malware -- viruses, worms, spyware and the like -- on your PC for years.

Is your phone the next battleground?

Security experts think it could be, particularly if it's a smart phone , a handset that has a full operating system and can run applications much as a desktop computer does. The more that phones can perform the same functions as PCs, the greater the chance they will have similar vulnerabilities, experts say.

"I'd put it in the looming-threat category," said Natalie Lambert, a senior analyst who covers mobile security issues for Forrester, a technology research firm. "There's huge potential."

Experts caution that consumers should put that potential threat in perspective. Other security issues -- such as simply losing a phone -- are arguably of more concern to mobile-phone users today.

"It's still very early in the game," said Chris Hazelton, director of mobile and wireless research at the 451 Group, a technology research firm.

Still, phones are indeed vulnerable to the same types of security threats that face PCs. Security experts have so far identified about 500 viruses or other types of malware or security vulnerabilities that target mobile phones.

Perhaps the best-known handset virus is Commwarrior-A, a piece of malware identified in 2005 that spread to phones using the then-current version of the Symbian operating system via text messages. The number of pieces of mobile malware detected since then has grown steadily.

Analysts say there are all kinds of ways that mobile malware could make mischief. Hackers already have induced phones to exchange text messages with rogue operators that charge a high per-message fee. Security experts worry hackers could soon use the GPS feature built into many phones to track the location of their owners.

Experts are alarmed that a new generation of spyware dubbed "snoopware" eventually could be used to turn on...