Since it reopened as a national monument in 1990, visitors to Ellis Island have enjoyed the re-creation of the immigrant experience—but gone away frustrated at the inability to access their ancestors' records there. Staff at the Ellis Island Immigration Museum have had to direct disappointed would-be researchers to the microfilm at the National Archives and Records Administration or at the Family History Library in Salt Lake City. The first five years of Ellis Island records were not indexed, making finding your immigrant ancestors a time-consuming, eye-squinting challenge.

That's all changed with the opening of the American Family Immigration History Center. Now, visitors to Ellis Island receive a card that lets the center's "interactive stations" gather up their findings for printout options at the end of the visit. (Web site visitors will also need to register before starting to search—it's free—so the system can keep track of your finds.) After a multimedia introduction to the island and its history, visitors are led through the steps to search for their ancestors.

Searching at the island or on the Web at www.ellisislandrecords.org works identically: An opening "Search Passenger Records" screen asks, "What is the passenger's name?" and has blanks to fill in first name and last name and check off gender. You can also enter just a first initial in the "First Name" field or even leave it blank. (Because of the sheer size of the database, however, you can't search without at least a last name to start with. Searches of, for example, all passengers ages 20-25 on the ship Acropolis in 1902 won't be allowed.)

The search doesn't use the Soundex system familiar to experienced genealogists, in which similarly spelled names are assigned a code to help ferret out misspellings and variations. But it does have a built-in filter that in many ways outdoes Soundex. "It's a computational linguistic search filtering that's sensitive to ethnic linguistic patterns," D'Arcangelo explains. "This was an essential feature, since there are so many places in the process where spelling errors can be introduced."

Next you're prompted to supply a year of arrival. (Again, remember, you're trying to narrow down 22 million database entries.) But if you don't know the exact year, you can enter a range of years or a term such as "before 1905."

Finally, you're shown a list of ethnicities (for example, "Gt. Britain Irish" or "Australia British") with entries that match the information you've already entered. You can then check any ethnicities that might fit your ancestor.

One more click and up comes a list of passengers who match your search. You're shown exact matches as well as lists of close matches and matches with alternate spellings; country of residence, year of arrival and age on arrival are displayed beside each name. Clicking on any name takes you straight to the digitized record.

Or, if your search turned up too many names, a box on the left of the results page lets you easily refine your "Passenger Search Profile." Here you can also search the database by age on arrival, port of departure and name of ship. (Savvy searchers with gaps in their family tree will be tempted to play around here: First cast a wide net with only surname, ethnicity and a broad range of years, then see who's there with the right age to be your ancestor, for example.)