I've got an iPhone 4, not quite sure which version of iOS, but I keep current.
Recently, I got an update for one of the apps, started it, and then for some reason it got stuck on "Waiting..." indefinitely. Another app later offered an upgrade, and when I accepted it got stuck on "Waiting...". This has been a few days now, with both 3G and wireless available, with no change.
The apps don't have the "delete" button when I touch and hold on them, and I tried deleting them in iTunes but after syncing my iPhone there was no visible change. (They're free apps, so deleting and reloading is a fine solution, but knowing how to kick-start the updater would be nice.) The App Store app simply tells me they've been updated.