Peter having just gone through this I have a couple of suggestions. First though I have to agree with Steven any information you get from us is worth what you paid for it... I have seen a PT for shoulder rehab once already so I was up to speed on what to do when I separated my shoulder.
This is probably the easiest thing to link to as it is a complete prehab/rehab protocol. I use the exercises in this a lot. http://www.youtube.com/watch?v=A0ONHZmsFec
This is another great video from Mike Robertson. In this video he does a great job explaining what muscles you are activating and how it should fee. http://www.youtube.com/watch?v=DlhBg...eature=related
The biggest challenge in using these exercises is that if you don't understand how they are supposed to feel you might miss out on the particular area that you are trying to activate. The main thing that I think about in all of theses exercises is scapular retraction and external rotation of the shoulder joint. Push Up Plus from the knees is still extremely painful for me today (I am 5 weeks post op on my shoulder) but I am doing them consistently.
The other big thing I can offer is to make sure that your pushing is balanced by doing at least the same volume in pulling. My goal is 2 to 3 times as much pulling work as pushing.
And yes I believe that this is something that needs to be done consistently if you have had problems in the past like I have.
YMMV and all the rest of that stuff. Hope that this helps some.