Spyware is the generic term for a computer application that records, without the knowledge of the computer owner, information about the user and browsing habits or other information and then transmits that information across the Internet. There are subsets of the kinds of applications that can be loosely described as spyware including adware, surveillance and remote controlling applications, and utilities that enable software to “phone home” to look for updates. Many of these applications have legitimate purposes while others are used primarily by hackers and individuals engaged in the harvesting of information for criminal or ethically questionable purposes.
The essential difference between spyware and legitimate applications is knowledge of consent. If you know the software is running on your computer, and phoning information home, it is legitimate. For instance, virus software, operating system software and applications like Adobe Acrobat all “phone home” to ask if there are newer versions, but these are legitimate uses of this technology
To get Spybot: (Windows only)
To get Ad-Aware: (Windows only)
To get Microsoft Anti-Spyware