I Used Windex on my screen. Now it's Stained. what can i do? HELP!

Not sure if there is anything you can do about it.

From the manual:

"Cleaning iPod touch
To clean iPod touch, unplug all cables and turn off iPod touch (press and hold the
Sleep/ Wake button, then slide the onscreen slider). Use a soft, slightly damp, lint-free
cloth. Avoid getting moisture in openings. Don’t use window cleaners, household
cleaners, aerosol sprays, solvents, alcohol, ammonia, or abrasives to clean iPod touch. "

I don't know, but there is probably a reason they warn you against using these cleaners.

I'm not sure how the inside of the glass would be stained.

You may need to either live with it or replace the glass.

there are some cracks too,

Woops! That 'raises the ante'. Cracks may have let the Windex solution reach the actual digitizer screen.

This page http://www.apple.com/support/ipod/service/prices/#us list the Apple out-of-warranty flat rate service fees in the US.

There are also 3rd party repair services for iPods.

Did you have a screen protector on your touch screen?

You can use Google to help you find a place.

OK, it's just the cover glass... do some Googling for places that will replace the glass. You might want to ask for opinions here about the places you are considering.

Your warranty doesn't cover such damage (cracking) and I suspect you will be quoted the flat-rate charge I referred you to --- but hey, you never know! Be VERY polite!!!

Great news!