There is some confusion with regard to CMap resources, specifically related to some resources that Acrobat uses that happen to use CMap syntax. Please keep in mind that a CMap resource unidirectionally maps character codes to CIDs. Those other resources that Acrobat uses are best referred to as PDF mapping resources. Among them, there is a special category called ToUnicode mapping resources that unidirectionally map CIDs to UTF-16BE character codes. There are four ToUnicode mapping resources: Adobe-CNS1-UCS2, Adobe-GB1-UCS2, Adobe-Japan1-UCS2, and Adobe-Korea1-UCS2.
In any case, I plan to initiate a separate open source project that will provide the PDF mapping resources under the terms of the same open source license, and expect that project to go live by the end of 2009.