Wirelessly posted (Mozilla/5.0 (iPhone; U; CPU iPhone OS 3_0_1 like Mac OS X; en-us) AppleWebKit/528.18 (KHTML, like Gecko) Version/4.0 Mobile/7A400 Safari/528.16) New version of documents to go is out. They added excel editing. So far it looks pretty good.
About time, too! Looks pretty slick. Unfortunately it's still not the all-in-one document solution as PDF viewing is still very basic - you can't search, bookmark or go to a specific page!