The folks at Alien Skin have shed some light on their plans for Photoshop CS5 compatibility:
Exposure 3 and Bokeh 2 are almost done and will be 64-bit on both platforms. Exposure 3 will ship in June and Bokeh 2 will be about two months after that. Since these are major version upgrades with lots of useful new features, we will be charging for them, $99 each. Free upgrades will be sent to people who purchased Exposure 2 or Bokeh in April 2010 or later.
Our other products will get free 64-bit and panel updates as quickly as we can do them. As they are done we will make announcements and the installers will be free to download from our web site. Most should be available this summer. We will be more specific about all these time frames as the work progresses.