There is a good chance that your fried the Wi-Fi chip, but there are some things you can try before giving up hope completely...
First, try resetting your iPod touch. Hold down both the SLEEP/WAKE and HOME buttons until you see the Apple logo appear.
If that doesn't restore Wi-Fi, then the next thing you can try is to do a complete "Restore" on your device.... Make sure you have your music backed up somewhere else as this will erase everything on your device and you'll need to reload your content onto it. Connect your iPod touch to your computer, select it in your iTunes Devices list, and hit the "Restore" button. This basically wiped the iPod touch and reloads the latest firmware, returning all settings to factory defaults.
Once the restore completes, you'll be given the option to restore the last backup of your iPod touch. Skip this step for now, as you can always restore this stuff later, and you want to test your Wi-Fi settings in a "clean" configuration. If your Wi-Fi still fails to work after this, and you've confirmed that it's not a problem with the Wi-Fi access point you're using, then sadly you're probably out of luck.
Note that water spillage is not covered under warranty, and the iPod touch has indicators inside so that Apple will be able to tell if you got it wet.