Here’s a press release from Adobe.
Adobe has released its Photoshop Camera Raw 5.4 Release Candidate, available immediately as a free download from Adobe Labs at labs.adobe.com. The “release candidate” label indicates that this update is well tested but would benefit from additional community testing before it is distributed automatically to all customers.

Great Tool for High Dynamic Range Imaging
Sometimes it takes more than one photograph to create that perfect image.  High dynamic range imaging (HDR or HDRI) has increasingly been used to improve the apparent dynamic range of digital photographs, or make the photo look closer to what you see.  And Photoshop CS4 Extended offers detailed tools [...]