Try resetting your browser if your using Safari, go to the Safari menu, about half way down there is a Reset Safari option, select that, tick all the check boxes on the following pop up window and press reset. Then go to the same menu and click on Empty cache.
Otherwise as others have mentioned run Firefox, it it a much better browser than Safari.
I had a similar issue with some websites a while ago, couldn't access them from my home on Mac, PC or iPhone, turn wifi off on the phone to force it to use 3g and the sites would work, turns out there was a glitch in the modem, a quick backup and restore / update of the modem software and it was all fine again (short of having to reenter all my port forwarding back into the modem anyway)
Nearly all men can stand adversity. But if you want to test a man's character - give him power.
Abraham Lincoln