Both of the titles refer to the same animated television series. The name was changed when the series was moved from the ABC network to the NBC network in 1961.

I could write an exhaustive article on this, but it's already been done! Take a look at Hokey Smoke! Rocky and Bullwinkle for the complete history of the series.

Here's a video I found which gives you an overview of the series, which is now broadcast regularly on "The Cartoon Network" cable channel: