Microsoft is slashing 70% off the list price of the professional version of its Mac Office software, but the discount applies only for purchases made on Thanksgiving or on Black Friday -- the day after turkey day.

Office for Mac 2008: Special Media Edition, will, including an instant rebate, sell for just $149 on Nov. 28, compared with its regular list price of $499.95. To receive the discount, shoppers must purchase the software from an Apple store, or from Best Buy Online or Amazon.com.

(Story update on 11/26@8:03am: Microsoft originally said the discount was 75% but later corrected the figure to 70%).

For those too afflicted with turkey hangover to shop Friday, Microsoft is extending discounts on Mac Office 2008 through New Year's. The Special Media Edition will be available at 50% off, or $250, after Black Friday.

Amazon appears to be jumping the gun on the special. As of Tuesday, the e-retailer was offering the Special Media Edition of Mac Office for $139, or 72% off the list price. Best Buy was selling the software for $250. The same price was available at Apple's online store.

Beyond productivity applications like Word, Excel, and PowerPoint, Office for Mac 2008: Special Media Edition includes Microsoft's Expression Media digital asset management tools and built-in Exchange server support.

Microsoft is but one of numerous tech vendors offering hot deals on Black Friday in an effort to boost what's expected to be a slow holiday shopping season. Dell, for instance, this week introduced a Black Friday version of its Vostro 860 laptop that will sell for $349.

Holiday shoppers looking for deals on tech gadgets might also do well at certain Circuit City stores. The retailer, which filed for bankruptcy protection earlier this month, is holding closeout sales at locations pegged for closure.