The soft keyboards already on the market for the iPad are crap. I know this because I have six of them sitting on a shelf collecting dust right now not 30’ from where I’m sitting.
I use the apple bluetooth keyboard. It isn’t a soft keyboard, but I keep it in my briefcase and it works great for me. My primary business uses are note taking in town meetings (I represent a couple of small towns) and other meetings; email and calendars, which update with iphone and my office pc whenever either I or my assstant input them.