Here was a very good article on software license auditing for businesses: (click here for story). The issues for businesses are twofold: (a) keeping track of the licensing that the business has purchased, and (b) keeping track and understanding the licensing agreements that control the software. The former can be handled by software. For example, Microsoft publishes Systems Management Server (SMS), which includes a software audit and metering tool. I understand that Altiris also offers a solution, and undoubtedly there are other packages out there that can tell you what’s running on your network.
The latter, however, requires a human being to review the software licensing agreement terms, and then analyze purchase history against the usage from the audit/metering tool. And the software license agreements themselves are often as clear as mud, especially if you have multiple, overlapping agreements for a variety of software packages. Even small businesses may have a substantial number of software packages and licenses they have acquired over time, so keeping up with this to avoid an audit can take real effort and concentration.