Google Multiple Sign-In

Google Multiple Sign-In:

This new preferences setting will allow users to sign in to multiple accounts for Gmail, Google Calendar, Google Sites, Google Reader, Google Voice, App Engine, and Google Code. I'm not seeing it in my account yet, but as with other Google upgrades, it'll likely show up soon.

With out seeing the integration, I'm unsure if this will negate my need for Mailplane, which offers multiple sign-in—and is about the only reason I'm using it.