In the Pre-Crisis version of the character, Lana played the equivalent of Lois Lane's role as a romantic foil in the Superboy stories. A grown-up version of Lana Lang later appeared in Superman stories, eventually moving to Metropolis to become a television journalist and a romantic rival to Lois, appearing in several issues of Superman's Girl Friend Lois Lane besides the regular Superman series.
In the Post-Crisis version, Lana was a childhood friend to Clark who eventually made privy to his abilities before he set out to use them for good. She made much less contact with Clark since then, but they share a close friendship.
In the television series Smallville, Lana, played by Kristin Kreuk is again the (often forbidden) love interest of the young Clark Kent, with at least some of each episode devoted to their potentially developing relationship.