While retailers have been tempting holiday shoppers all month with pre-Black Friday deals, the fiercest of the price-cut showdowns begins this Friday at 5 a.m.

Wal-Mart Stores, Best Buy, Target, JCPenney and Kohl's are already blaring their best prices online, offering lots of cross-channel options that make it easier for shoppers to choose store, web, or both. (JC Penney, which has vowed this will be its biggest Black Friday sale ever, is even pushing the insomniac envelope, opening stores at 4 a.m.)

Not surprisingly, Wal-Mart has been the most aggressive so far, and says it is offering an ad match program for any local competitor's printed ad for an identical product, including Black Friday specials. A Walmart shopper "has the comfort of knowing she doesn't have to run from store to store looking for the lowest price," says Wal-Mart Chief Merchandising Officer John Fleming, in its release. "We can deliver the best price to her no matter what -- we won't be beat."

Target, which has also vowed to be more price-competitive this season, has extended its store hours, with most stores staying open until midnight throughout the holiday period, and says it will match competitors' advertised prices. Unlike its competitors, it's hyping speediness and service, and says most of its guests will make it through checkout in less than a minute. Additionally, the Minneapolis-based chain has relaxed its return policy, and will now allow shoppers to return up to $70 in merchandise without a receipt.

"We've been watching the Black Friday advertisements, many of which have already been posted online, and after seeing Best Buy, Target and Wal-Mart's ads, there is no question in our minds that Wal-Mart has the best consumer electronics deals for Black Friday," Lisa Walters, principle at Retail Eye Partners, a consulting firm, tells Marketing Daily. "Wal-Mart is clearly pricing aggressively this season and we expect shopper traffic to respond. Best Buy will need to do something between now and Black Friday to counter Wal-Mart and Target's sales."

Kohl's, a leader in soft goods, says it will step up its marketing to make sure consumers know how low prices are going, including broadcast, online and print advertising, enhancements to kohls.com, direct mail, e-mail outreach and PR. This year, it says, it is upping its radio support in top markets the week of Thanksgiving, including DJ integration with personalities like John Tesh, Lia, Ryan Seacrest and Billy Bush. Online ads include advertising roadblocks on AOL, MSN and Yahoo.

Among its best deals: A $200 7" portable LCD TV for $70; $100 cashmere sweaters for $35, and 50% off its entire stock of Fisher-Price, Playskool, Barbie, Littlest Pet Shop, Hot Wheels, Matchbox, Tonka, Little Tikes, Crayola and Play-Doh toys -- a level of price cuts previously seen only at discount stores.