Rapper Eminem's "The Marshall Mathers LP" -- his second CD -- sold 1.76 million copies last week, making it the fastest-selling rap album ever, the biggest first-week of sales for a solo act ever . . . and enough to topple last week's sales record set by Britney Spears. Her "Oops! . . . I Did It Again" sold 1.3 million its first week. This week, she's at No. 2. The irony is that the foul-mouthed Eminem -- who was sued for defamation of character by his own mother -- openly scorns happy artists like Britney and *NSYNC. Speaking of which, "The Marshall Mathers LP" is second only to *NSYNC's "No Strings Attached" as the fastest-selling album in the nine years that the industry-tracker SoundScan has been keeping score.