Unsure of how Sprint plans work, but if you have the correct plan the service books are downloaded by doing the following on your phone:
Settings>Options>Advanced Options>Host Routing Table>menu key>Register Now. You should get a message saying, "registration sent" and receive an email saying "you are now registered on the wireless network...".
Once this is completed you may need to pull the battery and place it back in as well.
You can also check on Service Books by going into Settings>Options>Advanced Options>Service Books.
If this does not work your phone is either screwed up, or your service is not setup correctly.
Working for the dark side (AT&T) and fixing PDA/Blackberry issues since '03.