I've only sung one Eric Whitacre piece. It was "Cloudburst" and you can see that piece here. (Please note, I'm not anywhere in this choir, I sang it with Martin Luther College Choir back in 2006ish).
Here did a project back in 2009 called "virtual choir." He took one of his songs and had people individually record themselves singing one of the parts on a webcam and upload to youtube. You can see the very very cool finished result here. It turned out so well and was so well received that he did one of his other songs and it was sung by 2000 people and you and you can see that here.
Well, he's doing it again. Here's his official site. I haven't sung much in awhile but I really want to do this, so I'm starting vocal boot camp (which generally involves going on Flonaise to clear out all my sinuses, drinking copious amounts of water and singing vocal warmups every day) and then I think I will be singing Soprano 5 which involves one high A which I used to be able to hit but just barely and I'm rusty so...well...we'll see how that goes ;)