I think it's ridiculous for people to expect to move to another country and not learn the predominant language or assimilate into the culture, and instead expect the natives to accommodate and adjust to THEM.
That being said, I don't see any reason why English specifically HAS to be the official language of the US. It is the de facto predominant language here, ie. the vast majority of people who live in the US speak it. If, at some point, the vast majority of people in the US - legally, let me just throw in right now - spoke something other than English, then THAT should be the language we conduct business in and the one that new immigrants learn to fit into their new home.
In other words, my support is for the common sense idea of expecting the minority of new people to adjust to the majority around them, rather than the other way around. It isn't for English specifically. So no, I don't support an amendment ordaining English as an "official" language. I support the people standing up and telling their government officials to cut the PC, butt-kissing crap and stop costing us money in order to appear "multicultural" and "tolerant".