I was always having problems writing blog posts in Microsoft Word and then pasting them into TypePad as a post. I learned one thing to try. Save a copy of your document in Microsoft Word as a "Web Page, Filtered." This will get rid of a lot of that nasty Microsoft Word formatting that messes everything up. Then paste it into your blog.
Be careful though that you have another copy of your document because you will lose all of the Microsoft Word formatting except for links.
Here is Microsoft Office's article entitled About using filtered HTML
You can also try using this tool after you have filtered the HTML: http://www.textism.com/wordcleaner/
Note from later that night:
After reading the comment below, I couldn't resist downloading the Beta version of Office 2007 because you can blog with it. Beta means it still has errors they are working out. They say you should backup everything before using it. It costs $1.50 and is good for free until Feb 1, 2007. If you do get Office 2007 Beta, when it comes time to install it, click "Customize" and keep your previous version of Office. This is what I did. The big news with the new Microsoft Word is that the new documents will not be: .doc but rather .docx so you won't be able to open them in an older version of Word! Yuck!