This is a brand new 4th gen. On v. 4.3.5. My friend said he was going to download something cool and it got stuck. I later learned it was a tethered jailbreak.
Now there is a handy free tool, RecBoot, for Windows, Mac, and Linux users that can take an iPhone out of recovery mode. If you’re using the Windows version you’ll have to copy a specific (and proprietary) DLL into the directory that you’re running the app from, but after that you should be all set. Once you’ve done that you can fire up the RecBoot app and choose whether you want to Enter Recovery Mode or Exit Recovery Mode. If you’re reading this post you probably want to exit recovery mode, which will get your iPhone back into the state it was prior to entering recovery mode.
If you’re a Mac user you’ll see two different applications: RecBoot and RecBoot Exit Only. In this case you’ll want to use RecBoot Exit Only which will take your device out of recovery mode. The good news is that on a Mac you don’t have to worry about copying the DLL over, and it should just work out-of-the-box.
If your iPhone is stuck in recovery mode you’ll likely find RecBoot to be an invaluable tool. The fact that it’s free and cross-platform is just a cherry on top. (See if this works if not you may be out of luck)