Tempted to say use a tin opener but to be fair I must point out that microsofts software won't run on the iPad.
That said there are a number of apps you can use which can read word and excel documents and even edit them.
Take a look at Pages, Numbers, Goodreader and Documents to Go.
As to which is best I shall leave it to others to argue, but check out discussions of these apps in past forum postings.
