There is a higher level site from which you can try to navigate to App World. Here it is: http://worldwide.blackberry.com/my/appworld/download.jsp Once there you may be presented with a more up to date URL for your region. This is just in case the one I copied over to you above has gone out of date. Good luck.
Thank you! I tried the fore-mentioned solution (alt, rst), I managed to get to MyWorld through the browser, but when I clicked it, it froze again on MyWorld! Deleting Blackberry World and reinstalling worked perfectly and took less than 5 minutes. Thank you so much! Panic averted.