By the way, Balsamiq could be killer on the ipad. It already has a fun and tactile feel that fits the ipad perfectly. To Balsamiq: imo, you guys should just ditch flash and use your vision to make something much better in c/obj-c that includes lots of mobile and tablet components in addition to web. You'd have a ton of customers.
We are a bunch of indie developers who felt exactly this way! So, we cranked out a tablet app (both iPad and Android) that lets you import Balsamiq bmml files onto your device and edit/present your screens. Please feel free to take it out for a spin here: http://www.mockups.me/wireframes/tablet.html - any feedback is appreciated!