To every thing there is a season, and a time to every purpose under the heaven. Remember these words as you accept that your first-gen iPhone, iPhone 3G, and iPod Touches will not get the full Touch OS4 upgrade.
Apple's iPhone OS4 looks fantastic—but you're SOL if you are running an original iPhone or even a 3G. While that's not such a huge surprise for the original iPhone EDGE model—it's been a few years, now—it's shocking that the 3G, one of the most popular models and one that is still on sale, is getting the shaft.
Or at least part of the shaft. According to Apple, "many things" of the iPhone OS4 features will filter down to the 3G, but not multitasking, one of the standout features of the new version of Touch OS.
The same goes for iPod Touch users: Original model iPod Touch won't get any upgrade, while second-generation models will get the same "limited" version that the iPhone 3G receives.
Strangely, the iPad is seeing a similar sort of limitation: While the iPhone and iPod Touches are getting the upgrade by late summer, the iPad won't receive the OS4 upgrade until fall.
Apple did not comment on prices for the iPhone OS4 upgrade. I would expect it to work out like previous upgrades—free for iPhone, $10 for iPod Touch.