You can still redeem the free PS+ PS4 games if you plan to get a PS4 in the future, growing your PS4 game library even more for nothing!
Step 1: Go to http://www.sonyentertainmentnetwork.com and click on the links to get you to the Playstation store.
Step 2: Log in using your PSN account that has PS+ active
Step 3: Click on "Playstation Plus" on the left side menu, then "Free Games"
Step 4: Add all the free games from the list that you want to the cart (it by default shows you all the PS+ free games for the PS3, Vita, and PS4)
Step 5: When done, go to the cart and complete the order. The games are now linked to your account!
I'm currently doing this while waiting to get my PS4.