From Blogger Post Editor, you can customize your posts with custom permalinks setting. If you prefer to use a custom permalink, you can do so via the “Permalink” option in the Post Settings box.
example www.nameofblog.blogspot.com/2012/06/post-6.html .
The bolded area is the portion of the URL that is customizable.
If the custom permalink you entered ...
There is (deliberately) no feature for 301 re-directs in Blogger.
I assume that you plan to delete the contents from Blogger when you have moved them to the other site (to avoid duplicate content problems.)
You could set up a custom 404 error page which tells human visitors which website to find the contents (under Settings > Search Preferences > ...