I can't remember a lot about the story, except that Lois and Clark worked in different cities (I think she was in New York and he was in Metropolis? Or vice versa?) and they'd had dreams about each other for years but had never actually met. Then they do meet and they don't know they've both had the same dreams at first...but eventually they do. There may have been a Lana also in the story, not sure. Does anyone know what fic this is?
In Dreams by Kaylle springs to mind. That one has them in separate universes, dreaming about each other once a year. Clark is engaged to Lana because he thinks Lois is just a figment of his imagination. It's a really great fic.
Sorry, that wasn't it, either. It turns out it was Mayson, not Lana, in the fic - "Remember Me" by Matrix. I thought it was a much older fic than that, but apparently not.