An Apple press release today confirmed that they have moved about 2 million songs so far (about half of them as parts of albums).
The rate is slightly slowed from the first week (2 million in 16 days vs. 1 million in 7), but is still a very stong showing. Assuming the previous information about track sales from other online services is correct, Apple has now outsold its two main competitors' last year's sales by five times in a little over two weeks.
Additional music was added again this week (about 4300 songs) including a number of records by the Doors. (Can't you just hear "Don't you love iTunes madly"...).