iOS 5 isn't complete, nor officially released, so we can't officially comment on issues for unreleased partner software. We are currently testing, and working with Apple, and we will provide guidance on compatibility once iOS 5 is officially released.
Until iOS 5 is officially released, you can work around the crash with Photoshop Express in iOS 5 by turning off Location services. You can get there by selecting Settings > Location Services and then setting Photoshop Express to "OFF".
The tradeoff is that geotagging will be disabled and access to Review mode will be reduced.