Personally I find a spreadsheet to be the best bet. In the past I've used Tinysheet, but now I use Documents to Go (since that came free with my T3 and uses the expanded screen, which Tinysheet still doesn't)
Both of these synchronise with Excel, making it a snap to make major updates on a PC and just keep track of minor changes on the handheld. It also makes it really easy to take account of things like rage or spell effects or ability changes and see the knock-on effect on skills and attack chances etc.
I've got one or two of these, since I customise them for my characters. I'd happily email you (or upload here) examples if you think they would be useful.
Cheers