All of my Apps stopped working!!!!! worked fine until after I synched

Nice! Now not even newly downloaded or REBOUGHT (Yes I paid again to test) apps would run!

I wil start doing some tricks you are explaining here and will try to remember the steps and tell you whether it works or not...

Not only do all third party apps crash, but my phone tells me there are no songs, podcasts or videos either.

I tried all of the various suggestions short of restoring and/or deleting/re-installing all apps.

I am about to go on a vacation and will not have a computer available with which to 'fix' my phone.

One more piece of data. The same thing happened to me less than a week ago prior to the 2.0.1 update.

The prospect of not having the video to distract my daughter with during the flights is scary.

Yep, my phone shows no Music either, but when plugged into iTunes it shows that I have 6GB of music.....................

OK. This is what you do:
1. Sync your iPhone. Yes, you will lose functionality of any apps. Don't panic, it's not the end of the world.
2. Authorise your mac for the apps. Again, don't worry, it doesn't affect the number of computers you authorise.
2. Delete the apps from your iPhone.(press and hold the app icon, release, press the little 'x')
3. Connect your iphone to your mac. Launch iTunes if you have to.
4. Click on iPhone in iTunes>click Applications. You will see that the Apps are not checked.
5. Check all the apps.
6. Re-sync
7. Celebrate with a cold one, enjoying the fact that you have 'beat the system'.

APPLE: SORT THIS S**T OUT. YOU ARE CAUSING ALL YOUR (LOYAL & NOT-SO-LOYAL/SOON TO BE TOTALLY UN-LOYAL AND CAUSING YOU NOT TO MAKE YOUR NUMBERS...) CUSTOMERS STRESS, TIME WASTED AND HASSLE. GET IT SORTED. NOW. (or we'll visit you in the small hours and shove an iPhone up your nightdress - promise).

The method that I've had to use numerous times is
1. reset settings in iphone - settings- general (I use the first option which resets keyboard, signature, ringtones, brightness etc)
2. Unsync all music if it still doesn't appear on iphone
3. Unsync a few apps at a time - keep trying out remaining apps to see if they now work. Sometimes this had worked after removing 4 apps, at other times it takes many more
4. Once you get to the point of apps and music working, start adding back unsynced apps
5. Don't forget to re-input all your settings including any wifi passwords.
6. Keep iphone away from iTunes as long as possible and don't turn iphone off or allow battery to run out.

This method works for me and there's no guarantee it will work for anyone else. I've tried other fixes posted by others and this is the only one that works for me, but you're welcome to try it out.