st lets you edit Wiki pages from a Socialtext Wiki, even when you're offline, using your normal text editor, merging changes from the online site in as you go, and then uploading your changes when you're ready. It supports the checkout, update, diff, and commit commands from CVS, but instead of accessing a CVS repository, they access a Socialtext Wiki through Socialtext's REST API.
It requires a recent-ish Perl with the LWP and JSON modules installed.
You can download the software, browse the documentation, or browse the source.