Sounds proprietary:

Push email. Push contacts. Push calendar. In addition to Mac-to-Mac syncing, MobileMe now keeps your iPhone, your iPod touch, and even a PC in sync. MobileMe pushes new contacts, calendar items, and bookmarks to your Mac or PC, and over the air to your iPhone or iPod touch. For example, if you add a calendar event on the web, the change will automatically be pushed to your Mac and iPhone. New email will be pushed to your iPhone in seconds, eliminating the need to check for messages manually.