Like dhn says, if we don't know your model, we can't be sure if anything will work.
However, you can set up a free account at poi-factory.com. Having done that, you will find all of the RedBox locations at this link:
Redbox DVD Kiosk Locations - USA | POI Factory
You will see two download options - Garmin CSV and TomTom OV2. You want to download the latter.
Once you have that file (it's called "Redbox Kiosk Locations.ov2"), slide a copy over into your U.S. map folder on your TomTom. Again, without knowing your model, I can't say exactly what the folder name will be, but it should be pretty obvious and will contain U.S. or North America or somesuch.
Once you have the OV2 file in your map folder, power cycle your unit and see if you can find a Redbox entry anywhere in your POI list. If so, you're in business. If not ... well, sorry about that.