Can I use my Sprint HTC EVO phone overseas mainly in Europe or Africa?
Well, That depends.
If the country you goto has Sprint coverage, It will work but you will get extra fees depending on your plan. Usually your can add the International Calling feature to your plan.
Another alt. would be to unlock your phone so you can use a Prepaid service in the country you are going to. This is alot of the time cheaper than the International calling features carriers provide. This also depends on your phone it you can unlock it. To sum this up, it is basically it is swapping SIM cards for the service/country.