YouTube has been making a concerted effort to remove all the Downfall parody videos at the request of the German copyright holder of the original film, Der Untergang. However, my guess is that they are going to keep popping up and then disappearing. This one on the 2010 Australian Election this past Saturday (21 August 2010) will probably disappear as well.
Some of the parodies have been offensive. However, not all of them. Arguments that using Hitler as a backdrop to anything means it has to bad sometimes misses the point of spoofing a really obscure film about a homicidal tyrant by filtering the day's news through subtitles laid into the clip. The Huffington Post has a good read on the Downfall parody phenomenon.
So, enjoy it while you can.