Micko,
I took lessons for 9 years from the time I was 5 until 14. I stopped playing piano for 18 years and now at 32 I have a newfound joy in playing. I guess as an adult you learn to appreciate it more when the $50-$75 a lesson is coming from your own pocket

Personally, I did as the others mentioned and went to the local. I knew some composers I was interested in, so I looked them up. There are varying levels of difficulty in classical music, so you need an idea of what your capability is to play. A good teacher will quickly help you assess that and can also offer suggestions to you. For myself, I dove head first into some Bach and Clementi Sonatinas as well as refreshing my knowledge on major and minor scales and appreggios.
While classical music is not the end all, be all of music being played on the piano, it serves as a solid foundation of where music came from and the devlopemtn of technique you find in many contemporary pieces. Personally, I believe you develop an ear for classical music by listening to it and appreciating the sound and technique of it first. Then, you can begin picking up the subtle differences in variations, identifying the key changes within the piece, identifying the theme, and so forth.
First and foremost though, I urge you to ask a teacher or even one of the music store employees who may be able to help you identify what would interest you. Each composer has a different style and sound.
Take care,
Brian.