The most recent project is a Gmail Labs feature that lets you import and export filters. "Filter import/export, available today in Gmail Labs, helps you work with filters in bulk, rather than just one at a time. The basic function is simple: turn it on from the Labs tab under Settings, and from the Settings > Filters page you can download a file containing some or all of your filters or upload a file to create a set of filters all in one go."
You'll export an XML file that lists your filters. The file can be edited in a text editor like Notepad, using the format described here, with some changes. Hopefully, the Email Settings API will be available to all Gmail users, even as a simplified way of migrating Gmail's settings to a new Gmail or Google Apps account.
How to enable this feature?
Assuming that you have a supported browser, go to Gmail Labs, use your browser's find feature (Ctrl+F) to search for "filter import", enable the option and then click on "Save changes" at the bottom of the page. The new feature extends the Filters section from Settings by adding options to export some of the filters or import a file containing filters.