Hm. Seeing as I am a lot younger, and more into the newer stuff - or 80s stuff (Duran Duran, etc.) I never really learned as many songs from the older rock generation, so I can't help you with easy songs to play..
However, this is something definitely worth trying. This has been perhaps the best thing in helping me learn..
There is a program I use called Synthesia. This is basically a MIDI reading program, but what it does is brilliant. You input a MIDI file, and then it reads it, and then plays the song, showing you all the notes of all of the different tracks. Whilst it isn't quite the same as the real song, normally due to the MIDI limitations, it is extremely helpful in learning the bassline or melody of songs. You won't get as much traditional piano playing with these files, but you will be able to learn the bass-line and melody and string it together.. and I find this sounds great for me. Probably not a true piano player's dream, but if you can play a song well that's enough for me.
You are also in luck, seeing as there are way more MIDIs of older songs. It is quite hard to find MIDIs of newer songs, but with Bob Dylan, The Beatles, etc. there are hundreds of MIDIs on the Internet.
You can download Synthesia at
this link. It's completely free, and only 3.4MB.. which is sensational, considering how much I've used it.
Once you have installed Synthesia, you open it, it lets you choose a MIDI file, and from there you can choose the tracks you want it to play, and it will play the song, with the notes being shown on a piano keyboard. If you have a synth you can plug it in to your computer and play along, as well as score to see how accurate you get.. but I prefer just to learn the notes from this.
There are heaps of MIDIs all over the net, so it shouldn't be too hard to find!
I've included a MIDI of Let It Be, by The Beatles, for you, to get you started.
If this isn't what you are looking for anyway, that's fine - I just thought this might help. It's an extremely easy way to learn to play most songs, and despite being not traditional or conventional, it works for me.
Cheers.