Adobe Photoshop Lightroom is now shipping in the US for an introductory price of $199. In the UK the Adobe site allows you to pre-order the product for £146.88. The UK price represents a £50 saving, which can be taken advantage of until the 30th April 2007. Even though it is on pre-order, the shopping page does not mention a delayed delivery date, plus you can also choose to purchase as a 64Mb download, so my guess is that it is shipping straight away.
Of note, you do not have to choose a platform, so it would seem that you get both Windows and Mac versions in the same box.
I played with Lightroom in its beta days, but never really found a use for it in my workflow, but from what I did see, its non-destructive editing, superb interface and powerful features make it an ideal application for any serious pro or semi-pro digital photographer.