As an ESV fan, I was stoked when I tried out eBible.com, fresh out of beta, and found out that the ESV is one of the translations they offer! For the record, they have these translations: King James Version, New Century Version, The Message, New American Standard Bible, English Standard Version, New King James Version. No idea which edition of the NASB it might be, although I imagine it's probably the 1995 vintage. They also have seven commentaries, four Bible dictionaries, and ten encyclopedias. The Bible translations are all free, but a few of the other study helps have a cost associated with them.
They also have the concept of a "community" built in to the service; apparently you can invite your friends to the service and then share your verse, topic, and note bookmarks with the rest of them. Interesting concept, adding a social component to a Bible study site... but I wonder how well the whole thing will work out without the NIV on the roster.