Fairly quickly. Apple accepts the new iOS apps a couple of weeks before release so they'll be an initial bump in apps and then more and more apps start tricking in
Hi- Not being a developer (or even close)- what kinds of new/diff functionality will be available for use in apps with iOS5? Or is it mostly the msg/alerting apps that will need to be updated - similar to when multitasking was add.
they can be updated for iOS 5 with the iOS 4SDK, they won't be using the new iOS5 API's, but will just be bug fixes for things that they can do with the 4 SDK.