For text, any text editor will do. But if you're trying to "convert" copyrighted articles to post on your own site, modifying an article doesn't remove the copyright. The only part you own is the part you wrote yourself - the original words are still owned by the original copyright owner, and you're still subject to a takedown request.
if you just want to be unique, you can use spinnerchief or thebestspinner. If you want to make it readable, you can hire someone on freelance.com or odesk or someone from this forum Regards