How can I convert .ichat logs to text files?

How do you convert the iChat transcript files that Messages creates into human-readable text files that can be opened without the Messages app? For reference, these are the conversation files located in ~/Library/Messages/Archive. Simply opening the .ichat files in a text editor includes a bunch of additional strings and hashes. Opening them in Messages and copy-pasting into a text editor works, but I'd prefer to automate the process if possible.