I am not an electrician, but I may know just enough to be a danger to myself and those around me.
Is the freezer you are considering a 240 volt appliance? It probably is, and if so, you'll need a dedicated receptical. It's not hard to tell if you have one or not, as they are shaped differently from normal electrical outlets.
If you have one, then just plug it in and you're good to go.
If you do not have one, you'll want to have one installed. If you have to ask, "How?" then the best answer is to simply call an electrician.
With an old house, you'll want to have an electrician inspect it anyways, to make sure that your overall wiring is still sound. This would be a prudent thing to do regardless of whether or not you'll install a deep freezer.
Also, another reason why one should always contact a certified electrician is because states have different building codes about what is appropriate and what is not.
None of this should deter you, however, from having a deep freezer. Think of it as the infrequent but often times necessary evil of paying the termite guy to inspect your home.
Once you have a freezer though, please be absolutely sure that it is connected to a dedicated receptical that goes to a dedicated circuit breaker in your fuse box. Unlike the small lamp on your nightstand, this is a major appliance that you want to be sure to protect against any short circuits.