iFixit has a whole bunch of useful guides that are free and include images.
If you think that it's the LCD that's broken, follow this guide. Looks pretty simple. You can order an LCD and all the required tools from that site too.
Quick Google of the 'ipod touch white screen' reveals that this is a common issue and can sometimes be resolved using software fixes. I'd take a look through the linked youtube videos or the guides and see if that works before prying it apart/ordering anything.