Hey,

There are a lot of resources and materials available. I cleared both the exams and used the following books:

For theory: NPTE by Sullivan - often called the US license exam book. If you are thorough with this book, you will do fine.
In addition you can also browse through The big sullivan-Red book on rehabilitation, Magee- Ortho assessment , and Therapuetic exercises- Colby and kisner.

The same books would be useful for clinical, but make sure to practice some cases with friends or groups. This is the single most useful technique.

Also for clinical if the pthealth course is being conducted in your area, make sure to register and appear for their mock exam. The alliance also offers some course,not quite sure about it.

Hope this helps.

Good luck!!