When I started I used Justin Sandercoe's website. Very helpful. But in the end, I found that a teacher was the only way I could move past any places where I got stuck. Whether it was the mechanics of a particular song, or motivation on my part that stopped my progression....a teacher always got me moving forward again. Mind you, I am not talking necessarily about weekly half-hour lessons, either. I actually do best with one-hour lessons every two to three weeks or so.
Oh, and I too continue to play the songs I learned a few years ago and play relatively easily now. I find that I can always improve on them (timing, musicality), and playing them also makes me appreciate how far I've come.
Good luck!