Apple ipod

iPhone OS 4 (4.0). Questions?

I have an iPhone 3G and I do not know what four new operating system. I do not understand, is an update of existing phones or is it a new phone line? And if there's an update, is it free when the release date? Thanks in advance

There will be free for you, is published in the summer and is a software update for your phone – To allow him to do more things and more aesthetic look. There many improvements in version 4.0.

iPhone OS 4.0 Release Date?