If your Iphone is stuck on the white apple logo.
Do the following to avoid having to restore.
I can not take credit for it as I found the solution on the web.
However it worked for me.

Press and hold both the sleep/wake and the home button until the phone restarts.
Connect the phone to the computer with the usb cable.

After a few minutes when you here it connect on your computer.

Start iphone browser, iphone pc suite or your SSH program (Winscp).

go to /System/Library/SystemConfiguration/mobilewatchdog.bundle

and rename both files by adding ".test" to the end of the file names.

Restart your phone by holding both the sleep/wake and the home button until the phone restarts.

Now wait for your phone to go to your lock screen. (may take a few minutes)

Now that is is back to the lockscreen do the same as above but this time remove the ".test" from both files in /System/Library/SystemConfiguration/mobilewatchdog.bundle

and restart your phone.

Thats it.

thnx for d info. It may come handy someday

LOL I had the same problem today and couldn't remember how to fix it. Then it clicked, that I had posted it here. This always happens when using Iphone PC Suite.
I guess I saved my own bacon.