I've been having a this problem with my MacBook recently. In most cases the airport says full signal but I have no access to the internet. During the last two instances, I checked other wi-fi devices (iPod Touch/iBook/Samsung Omnia), all of which connected online perfectly while the MacBook couldn't. This usually passes after between 5 and 15 minutes, but it is exceedingly annoying. The other problem with the Airport is that it doesn't pickup any signal at all sometimes, not even finding the other networks that are normally found. Last time this happened, I found that I could connect to the local network if I manually entered the information under TCP/IP, but still couldn't connect online. Changing back to DHCP did the trick, but until I manually entered the information, I couldn't even find any networks. This is an intermittent issue, occurring about twice each day, but it is rather disruptive. Does anyone know what the problem could be? Help would be greatly appreciated.