FLAC is an open source project and we are happy to enlist the help of anyone who wants to contribute, or to help with FLAC support in other programs and devices. The preferred method of communication is the developer mailing list
(you must subscribe to post).
FLAC is open to third-party developers who want to add support for FLAC into their programs. All the necessary functionality is contained the libFLAC libraries which are licensed under Xiph.org's BSD license
Some pointers to developer documentation and code:
More resources are available on the FLAC project page