Recently purchased a new Intel Core 2 Duo iBook and have had no problems using it to connect to wireless networks in hotels, airports etc.
The first time I brought it into my office it recognised my Belkin F5D7630-4A router network (homenet) and asked if I wished to join it. At that time I had a 128 bit hex WEP key in place and I duly put this into the Mac. After a few seconds it came back with the message "there was an error joining the airport wireless network homenet".
Repeated attempts failed and even long phone discussions with Mac and Belkin support failed. I have a PC elsewhere in the building which connects wirelessly to the belkin, no problems there and I can connect the iBook using an Ethernet cable.
In desperation I removed the WEP security from the router, leaving a completely open network. Once again the Mac sees it and offers to connect but subsequently throws up the same error message.
I have scoured the net for a solution and have found a number of people with similar problems. In particular an article at: http://www.mac-forums.com/forums/showthread.php?p=308792
seems to reflect a near indentical problem.
Since having this problem I have still been able to connect the Mac wirelessly to Hot Spots etc. in a variety of places.
Any ideas, greatly appreciated.