This is a cautionary story for all of those iOS 5 users out there, including the new iPad 3 users. Germany security firm MajorSecurity discovered a bug earlier this month that can be used to trick you into visiting potentially malicious Web sites. The bug was first discovered in iOS 5 and was replicated in iOS 5.1. Apple was informed of the bug by MajorSecurity on March 3, but has not yet issued a patch.
Apple has acknowledged the bug, so they should be able to produce a patch, and I would encourage you to upgrade when it becomes available. Until then, watch the sites you go to, as it may not be where the URL bar is telling you you are at. If you would like to see for yourself, go here on your mobile device, select Demo in the upper left corner. This will open a new page that says Apple and looks like Apple but is still on MajorSecurity's server.