The URL's for iOS 5, Lion Developer Preview, and iCloud beta have all been leaked. These are straight from Apple's servers. Some of the files may not be live yet.
Interestingly enough, iOS 5 will support the 3GS, something that was rumored to be discontinued. Also included is iTunes 10.5, Xcode 4.2, Safari 5.1 and much more.
You get that because A) you are not a dev. and B) the keynote is still going on, they dont upload the files instantly after ios5 is announced, itll be a few hours.