Before you disconnect your Sprint service make sure you've chosen a new carrier - you can easily keep your number and move it to another carrier. Its much easier to do this if you have a current plan live as sometimes carriers will disconnect your number and allocate it to somebody else once you have disconnected the service.
If you own an unlocked Sprint device, you'll notice there are a wide variety of service providers who are accept Sprint phones. In order to successfully switch carriers, the first thing you'll need to do when attempting to switch carriers is have the phone unlocked.
Once the phone has been unlocked, you can begin shopping for your new monthly service plan. To help provide guidance and make things more efficient, below is a link to the available carriers and plans which your Sprint phone will work with.
Transferring your number to the new carriers is really easy - its part of the activation process which you can complete on-line or over the phone with your new carrier. Generally they need your number and account reference to make the switch over.
Once you're ready to purchase and you've found a phone or a plan that you are interested in, simply select the blue button titled "go to site". By clicking on the blue button titled "go to site", you'll be taken to the carriers website to begin completing your purchase.