I’ve always recommended that people not paste text directly into WordPress from Microsoft Word, and instead suggested that they open their Microsoft Notepad, paste into Notepad, then copy and paste back into WordPress. This extra step removes the stupid formatting put in place by Microsoft Word.
Apparently, a recent addition to WordPress (maybe 2.3?) added a button on the WordPress text editor that allows you to paste information directly from Microsoft Word, and instantly strips out all the formatting. I’m exactly not sure how long it’s been there, but it works very well.
First you have to open the advanced toolbar options to see the new button button –
This expands the menu to a second level where you will immediately see the option for Microsoft Word pasting.
Hitting that button opens another small window, where you can paste from Word to your hearts content.