With the plethora of PDAs available in the marketplace, is the "push" capability--for which the Blackberries are so popular--available in any other devices?

I have been wondering this because, although I'm addicted to my Blackberry (which I affectionately call my Crackberry) because of receiving e-mails instantly, it does not seem open-source friendly and this is important to me. I get to use a lot of free software that is on-par with the closed-source stuff, but I cannot sync the Blackberry with standards-based, open platforms like I could do with a Palm-based device.