Britney Spears [ tickets ] postponed the beginning of her tour due to her case of the flu, but tickets to her shows are still hitting box offices in at least three cities this weekend. Spears will be supporting her forthcoming album "Britney."

Tickets will go on sale at 10 a.m. Eastern Time on Saturday (10/20) for her performance at Madison Square Garden in New York.

At 10 a.m. Central Time on Saturday, an on-sale has been set for Spears' shows in Milwaukee and Minneapolis.

Click here to read more about Spears' tour.

Tickets will be available for Brian McKnight [ tickets ]'s performances in Upper Darby, Pa., and Sunrise, Fla., at 10 a.m. Eastern Time on Saturday (10/20).

Click here to read more about his tour.

Tickets go on sale on Saturday (10/20) for at least six Merry Mayhem shows featuring Ozzy Osbourne [ tickets ], Rob Zombie, Mudvayne and others. A 10 a.m. on-sale date has been set for shows in West Palm Beach, Detroit and Manchester, N.H.

Fans in Des Moines, Iowa, can purchase tickets beginning at 10 a.m. Central Time.

At noon Eastern Time on Saturday, tickets go on sale for the show in Grand Rapids, Mich. Meanwhile, in Madison, Wis., tickets go on sale at noon Central Time.

Click here to read more about the Merry Mayhem tour.

Barenaked Ladies [ tickets ] have announced more dates for their winter tour. Tickets go on sale at 9 a.m. and 10 a.m. Eastern Time on Friday (10/19) for performances in New York City and Newark, Del., respectively.

Natalie Merchant has scheduled a slew of on-sales for her fall/winter tour.

At 10 a.m. Eastern Time on Saturday (10/20), tickets go on sale for her show in Pittsburgh.

Fans in Louisville, Ky., and Kansas City, Mo., can purchase tickets beginning at 10 a.m. Central Time on Saturday.

A 10 a.m. Saturday Mountain Time on-sale date has been set for her show in Denver. Tickets for her performance in Seattle go on sale at noon Pacific Time on Saturday.

In Oakland, Calif., tickets go on sale at 10 a.m. Pacific Time on Sunday (10/21).

Click here to read more about Merchant's tour.

Harry Connick Jr. has announced concert dates in Nashville, Minneapolis and Chicago. A 10 a.m. Central Time on-sale on Friday (10/19) has been set for his show in Nashville. Fans in Minneapolis can purchase tickets beginning at 10 a.m. Central Time on Monday (10/22). At noon Central Time on Monday, tickets will be available for his Chicago performance.

Click here to read more about Connick's tour.

Tickets for Amy Grant and Vince Gill's performances in Columbus, Ohio; Cleveland; Minneapolis; Dallas and St. Louis go on sale this weekend.

An on-sale time of Friday (10/12) at 10 a.m. Central Time has been set for the show in St. Louis.

Fans in Columbus and Cleveland can purchase tickets beginning at 10 a.m. Eastern Time on Saturday (10/13). Tickets go on sale at 10 a.m. Central Time on Saturday in Minneapolis and Dallas.

Click here for more information about their tour.

Lonestar has announced three new performances. Tickets go on sale at 10 a.m. Eastern Time on Saturday (10/20) for its shows in Cincinnati and Winston-Salem, N.C., and fans in Peoria, Ill., can pick-up tickets at 10 a.m. Central Time.

Tickets go on sale at 10 a.m. Central Time on Friday (10/19) for Melissa Etheridge's two shows in Dallas. At 10 a.m. Central Time on Saturday (10/20), tickets go on sale for her show in New Orleans. Meanwhile, at 10 a.m. Mountain Time on Saturday, fans can purchase tickets for her Albuquerque show.

Click here for more information about Etheridge's tour.

Ticket on-sale information for many other shows is available at liveDaily's Ticket Alert.

Unless otherwise noted, tickets are available from Ticketmaster and Ticketmaster Online, as well as the venue box office. Ticketmaster is liveDaily's parent company.