Early this year Google released Google Sync, which makes your calendar and apps work is if they were on an Exchange server. Missing from the app, of course, was push capability for Gmail.
That day has come, people.
Google just announced that Google Sync now supports push Gmail for Windows Mobile (5.0 and higher). The usual caveat applies, however: If you're already using an Exchange server for other e-mail, you're out of luck.
Get the full deets here.