Everyone who has PS+ will have access to the same games. Now you won't be able to play the PS4 games they offer on PS3. At the moment it is unclear if you can add these games to your download Que. If it turns out you can then I would do so , so you can get the game for free once you have your PS4. The way PS+ works now is all you gotta do is que it up for a download and it will always be there for you even if it leaves PS+. Like i said tho atm its unclear if you can Que the download if your not on PS4. With sony pushing mobile and always connected im sure you will be able to as your download Que will most likely be in the cloud but that remains to be seen.
I will ask around and see if i can get a better answer for you.