So I was just merrily arranging a couple of new apps I downloaded, and pushed some on page 11 to the nonexistent page 12. I have no idea how to get them to come back... I feel stupid, but help would be greatly appreciated...!
Plug it into iTunes. There you can easily delete the apps you dont want (so you only have 11 pages worth of apps) by unchecking them. Also you can move the old apps back to the visible pages and push the unwanted ones to the hidden pages if you wish. And I hope you know the apps in 12th page just moved past the visible pages but they are still accessible if you search for them in spotlight.
The checkmarks for the apps you want to delete (if you want to delete them completely ie). All apps have a checkmark in with their names. You can check/uncheck the ones you want to keep/delete from your iPhone.
Ah, OK. Thanks for clearing that up! It's quite silly that one can only have 11 pages of visible apps. Is there a good reason for that?
Scrolling so many pages will get tedious. 11 is already too much to remember which page has your app. And with iOS4, you'll be getting folders in just about 2 weeks. Which will eliminate the need to have so many pages. Much better option compared to having an endless number of pages.
You can also just reboot and your apps will come back. If the first two pages are full and the app you pushed out is a system app (like voice recorder) then you'll glitch yourself a new page! If you have multiple blank spots, downloading an app on your device will cause the others to return from the hidden pages... You can find them on search if you want to. I've got around 500 apps on my iPod, I'm very much looking forward to folders!
Delete some you don't need and go to Settings > General > Reset > Reset Home Screen Layout. No need to restart. All apps (except front page) will sort alphabetically. If you want that...