[UPDATE - 12/27/2008]
MB noted in the comments that the Cyber Hymnal is back. It's certainly good to see this important resource available again.
I ordinarily go to cyberhymnal.org to look up the words to hymns, but that domain name seems to have been taken over by a company that offers vacations, insurance, online dating, and so on. I wonder if someone forgot to pay the registration for the name?
That would be too bad, since they have been around since the mid 1990s providing an excellent reference for those interested in hymns and their history.