Usually ebay is your best bet, but if you have an 8GB 3rd gen, then you can use 2nd gen parts ([http://www.ifixit.com/iPod-Parts/iPod-Touch-Gen-2-Front-Panel-Assembly/IF140-003|this] would then be the part you could use). If not, check ebay, and you should be able to use [http://www.ifixit.com/Guide/Repair/Installing-iPod-Touch-2nd-Generation-Front-Panel/1125/1|these 2nd gen] installation instructions, won't be that different.