I got a slight shock today as I read online that starting today new rules apply to traveling to the US. According to the new rules if you intend to go to the US under the "Visa Waiver" program you now have to apply before hand at least 72 hours prior to departure (And up to 2 years).
You apply by going to this US Customs & Border Protection site. If for some reason you are denied you then need to apply for a normal Visa at the US Embassy.
The reason why I was so shocked when reading this is that it is today around 40 hours left until I am about to board a flight to the US and this was the first time I've heard about it (You would think that the airline would have told you about it). Fortunately though after a frantic call to the US embassy here in Stockholm I was assured that since I have a work visa this doesn't apply to me.
All you people planning on coming to visit though, don't forget to register in advance.