said 1 year, 2 months ago:
Yes, this will change the URLs of your blog posts. If you have posted them elsewhere, then it will change their address, sort of like you moving to a new house and not telling anyone.
However, if you haven’t put them out there too much, and they haven’t been promoted that heavily, then go ahead and change them. Google will keep up without any problems.
It would definitely be worth doing, especially if the update will change the URL of your blog post to include the actual title, and not “p=1168″ or whatever identifier they use.