From: vnunet.com

Ransomware attacks target Symbian mobiles

Researchers have discovered malware which holds mobile phone data to ransom.The malware removes all sent and received text messages, and threatens to permanently cripple the handset unless users pay a fee.

Phishbait editors observe:

Phone-related attacks - both Symbian and Windows Handheld - can be spread via SMS / text messaging. So take care when responding to a message you don’t recognize.

Your mobile NEEDS anti-virus software as much as you regular PC does!