Check some of the fitness sites stickied in the first thread in the forum. I found particularly useful the USTA Player Development routine, which works great if you have limited gym access (all you need is a court, medicine ball, and exercise bands).
Aside from the free sources, you can consult with a personal trainer, who can design a program that suits your needs. The investment may be justified in light of your shoulder issues.
3x Yonex RDS001 MP
Alpha Revo 4000