Hi: I have MacScan installed on my MAC. What it does is search for spyware, tracking cookies, keystroke loggers and other such malicious items. The first time i ran it, it found two or three tracking cookies which i deleted. Since then it has found nothing bad.
A trial verson can be installed free and if you find it useful it costs $29.95.
Here is their summary of what it does:
"MacScan 2.5.2 - Detect, Isolate and Remove Spyware
MacScan 2.5.2 Release Date: 4/1/08
Demo Terms: Demo will expire after 30 days
Requirements: OS X 10.2.4 or higher, Internet connection required for updates and activation.
Catalog: Administration, Security, Mac OS X
========READ FULLY BEFORE USING MACSCAN==========
In short MacScan's goal is to detect, isolate and remove spyware from your system such as keystroke loggers and trojan horses. Keystroke loggers are programs that are used to record everything that is typed on the keyboard, and log them to a file. Some keystroke loggers will send the logs over the Internet to a specified address programmed into the application. The loggers are not limited to what text they record, if you're typing a letter, or typing your credit card or social security number it is all logged.
Programs exist that, when installed and/or running, allow a remote user to connect to your computer over the Internet, network or telephone line, effectively taking control over your computer, including the files stored on it. There are two types of these programs: Commercial ones, which cost money and allow remote administration activity, and the ones that are intended for control over the computer without the user's knowledge of the activity. MacScan will not remove any of the commercial remote administrative applications. It will however, make the user aware they exist on the computer in case they were activated accidentally, on purpose without acknowledgement, or the administrator forgot to deactivate after use. The other type of programs, commonly known as backdoors or trojan horses, are identified by MacScan and are can be detected, isolated, and removed.
Protect your privacy by checking for known programs which could be running without your acknowledgement by running MacScan. We're always adding more support; if you find an application that is currently not detected or is not being detected properly, please contact us via the contact information below."