Using attachments in messages and wikis

I have been playing with the Communities plugin, for working and exchanging written content this is a powerful tool. Now, I would like to be able to use file attachments in the message boards and wikis. The same functionality would be great if available for the Messaging plugin.

Does anyone know how to solve this using an existing plugin? If this is not possible, I would like to get some guidance on how I could get started developing this functionality as an extension for the plugin if possible.

Thank you!