Wi-Fi troubleshooting suggestions
I suggest you start your problem solving by reading through the following documents:
iPod touch: Wi-Fi Information and Settings at http://support.apple.com/kb/HT2031
iPod touch (2nd generation): No Wi-Fi indicator on the Home screen and no wireless network connection after resetting at http://support.apple.com/kb/TS2199
Unable to use Wi-Fi with iPhone or iPod touch because there's no Wi-Fi address listed for the device at http://support.apple.com/kb/TS1559
iPod touch and iPhone: Tips when using Wi-Fi at http://support.apple.com/kb/TS1398
933mhz G4 Quicksilver with 10.3.9 - 1.33Ghz G4 12 Al PowerBook with OS 10.4.11., Mac OS X (10.4.11), I DO NOT receive any form of compensation from my recommendation or link.