No, you change it to Home Only. Settings -> Wireless & Networks -> Mobile Networks (bottom option) -> System Select and 3 options appear. There is Automatic, Affiliated Networks, and Home Only. Home only will only look at Sprint towers. So far so go here. I still checked all the boxes for roaming regardless just because hahaha. But.. as of when I did that this morning. I haven't had any 'waiting for coverage' (Pandora/Tweetcaster error) or hang ups when downloading anything yet. We shall see though, I especially want to see if this wifi change fixes my problem at home. The connection is low in my room so it drops in and out. If it were to hold a connection at low and work, id actually be very happy.
Again its not a fix, its a workaround as this shouldn't be needed. However, I got the phone for 50 bucks almost 3 months ago and the hardware is beastly (minus the radio) :-\