One issue that may be causing is that the router may be sending a 802.11n (WI-Fi N) signal. It is the the latest standard that while has the furthest range over the previous standards 802.11a/b/g, older cards are not able to connect to these routers. While the latest iPod touch has the necessary chip, the N support hasn’t been activated by Apple for some reason. This may explain why your laptop is able to connect to the network, and your iPod isn’t. Try connecting to a several other networks, if it connects then my hypothesis was correct. If not take your iPod in for a look at the Genius Bar as the wifi antenna may be malfunctioning, in which case they should replace it for free.