Quick and easy fix 1: Upgrade to iWork 09. It automatically zips up .pages, .key files, so then can be managed / versioned in Alfresco as files. Or any other system for that matter.
Fix 2: It should be possible to configure / extend Alfresco to handle these file types. The effort involved will depend on how which interfaces in Alfresco you'd like to use. I.e. Alfresco webclient, CIFS, FTP, IMAP, etc.
Please, note full text search and content transformations will not as Open Office does not support iWork documents.