Yep - using iAnnotate PDF - basically I'd rather not print out pages and pages of dead tree, but still need to get away from a traditional computer screen to lose some of the word blindness you get in that mode. Plus, no more covering myself in highlighter pen
I've still got to figure out the workflow, but if it works, it's my killer app. I'm fairly optimistic, as I was reading a review from a published author the other day who uses his iPad in a similar way.