There are two new databases at Ancestry.com that struck my attention this morning:
The Alien Arrivals appear to be indexed. The first image on this blog post comes from a list from that database dated 8 April 1849. I was hoping to find one of the various members of the Frame family, but no avail.
Unfortunately the UK, Aliens Entry Books are NOT indexed. This was a huge disappointment as my wife has several UK natives who likely naturalized in the United States and returned to the UK for a visit. Hopefully in time it will be indexed.