Dataviz has Documents To Go for the Palm, it opens Word 2007 documents read-only. Dataviz has announced Documents To Go for the Blackberry, but it's been 4 or 5 months and it isn't released yet. Moreover, there are rumors that the new 4.3 OS update is going to include Documents To Go, which I find hard to believe, but anyway.

Short answer: no, there isn't, but there might be soon... ish.