On June the 7:th the Steve divulged that iOS 4 would be available today for iPhone 3G, 3GS and iPod Touch users.
It’s rumored that the update will be available after 18.00 CET(according to Telia, a swedish provider). To check if it’s available, just hook up your device to your computer and start iTunes.
But make sure you have updated your iTunes to version 9.2 as it is required to support iOS 4!
If you’re not up to speed as to what iOS 4 might offer you, have a look at this vid for a 10 minute briefing of what’s new in iOS 4.