Restaurants and bars from coast to coast are hanging Union Jack bunting and hosting gatherings to watch the wedding on live TV, complete with royally named cocktails, including "The Windsor Knot" and "The Bitter Queen."
Large events are planned, from a live viewing party in New York's Times Square featuring singer Colbie Caillat, to Walt Disney World's party in its Wedding Pavilion with 250 guests invited to wear prince and princess attire.
And in private homes across America, royal watchers are hosting their own get-togethers with scones and cucumber sandwiches. In Indianapolis, Jen Barnette, 24, will have her girlfriends over for a "Kate-tail" party and sleepover. The living room will be set up as if for a wedding, with rows of chairs -- lined up in front of the TV -- and a runner-lined aisle. The guests will wear Will and Kate t-shirts.
"I made mock invitations that look just like the royal invites," Barnette said. "They all get a copy-Kate ring. We've even got Kate-tails, sapphire blue with sugar rims."
Michelle Ertel asked her husband to wear his tuxedo and act as a butler for about two dozen members of her women's club in Oviedo, Fla. Two large-screen televisions will show the wedding as it happens and Ertel, a 43-year-old communications consultant, has asked her guests to each donate a special occasion dress for charity.
The royal wedding is a chance to see the kind of life few in America are familiar with, said Ertel, the mother of two teenagers. "We get up. We go to work. We take care of our kids. We go to bed," Ertel said. "We don't live like that. It's a vicarious thing."
The wedding may be a bit surreal for Kate Middleton, 35, a stay-at-home mother of a 16-month-old daughter in Milton, Mass. The future princess' namesake will watch the wedding, but not in the early morning. She said she has saved some of the magazines that say "Kate Middleton, a perfect princess."
"Who wouldn't want that?" Middleton said. "When I went to get a haircut, they were all excited when I walked in. When I went to Gymboree, also the same thing. They were like `Oh are you Kate Middleton?"'
Wedding planner Erin McLean, 31, is having a breakfast party with her girlfriends in Raleigh, N.C.
"I made little British flags that we're going to put in the drinks," McLean said.
Parties will be going on throughout the day -- from early-morning breakfasts to afternoon teas and evening dinners -- at American restaurants and bars, said Nina Zagat, co-founder and co-chairwoman of the Zagat restaurant guides.
"Restaurants everywhere seem to be doing something," Zagat said. "It is going all the way across the country. Everybody is taken with the idea of the royal wedding."
AGAINN Tavern in Washington D.C. will be selling slices of cake similar to those the royals will be eating: chocolate biscuit cake -- Prince William's favorite -- and a traditional royal wedding cake made with fruitcake. Customers who bring a teapot will receive a free appetizer or dessert. Wedding bunting and Union Jack flags will decorate The Globe Pub in Chicago, where classic British fare including fish and chips and full English breakfasts are on the menu.
For other Americans, the royal wedding is not only a time for celebration, but also contemplation. Dozens of members of Chicago's Episcopal Church of Our Saviour will gather early Friday in the parish hall to watch what they consider a major event in the Anglican religion.
"It's part of the culture that we've grown up with," said parishioner Roger Gumm. "This is how our church runs. This is all history in the making."