An easy way is to get Office2 HD or Quickoffice HD (or one of the free PDF viewers) and a Dropbox account. That way you can Dropbox stuff to yourself. You then have the option of emailing someone a Dropbox link to share a file or simply emailing it as an attachment from within the App'. Office2, Quickoffice and all free viewers, will extract PDF's from emails as well.
I hope this helps.