Instant Messaging (IM) is one of the fastest growing Internet applications. The recent debate about IM is related to the broad issues of open access rules and competition in the high speed Internet service and cable television markets. Although IM technology has evolved largely independent of formal regulation, a review of the AOL-Time Warner (AOL-TW) merger brought issues of interoperability (the ability to exchange messages between multiple IM services) among IM services under scrutiny both in the US and Europe. Concerns about open access and accessibility for the disabled, have been raised by Members of Congress, the Federal Trade Commission (FTC), the Federal Communications Commission (FCC), and the European Commission (EC). These issues highlight the growing complexity of regulating converging technologies. This report discusses the technology behind instant messaging and provides an overview of the issues. It will be updated as necessary.