how can I repair a cracked itouch screen

Apple will exchange your iPod for a refurbished one for:

Apple - Support - iPod - Repair pricing

A third-party place like the following may be less expensive. Google for more

iPhone Repair, Service & Parts: iPod Touch, iPad, MacBook Pro Screens

Replace it yourself

iPod Touch Repair – iFixit

eBay and Google are your friends. Let your fingers do the walking and search the web... The answers are out there.....