you should check that your wireless is turned on from your router, if it is, and this doesn't seem to be the case, try completely resetting your router and reconnecting on the device, if not, turn wifi off completely on your ipod and leave it for a while, then try reconnecting to your wifi ensuring all passwords phrases/keys are correct e.c.t. if all this fails:
You should go to your internet settings on the ipod and change it from default to your actual internet connection..when i have problems with the wifi, i just turn my wifi off, and turn it back on.