Go into [Hard Drive] -> System -> Library -> CoreServices
Find "Captive Network Assistant" and rename it to "XCaptive Network Assistant".
Voila! No longer a problem.
This is at least a temporary fix to resolve the issue until Apple fixes the problem at their end (who knows how long that is going to take).
In terms of overall impact, it will only affect people on corporate networks or airports that need to input corporate usernames/passwords. If you're just connecting to your wireless at home it won't have any impact.
This is one of the reasons I suggest also not "deleting" the file and instead "renaming" it to get it out of the way, temporarily whilst Apple fix the issue so you can then rename it again after they fix what they need to.
At least it won't get in your way every five minutes whilst trying to surf the net.
Anyway, hopefully that helps everyone.
Regards,
Wyrmfire