The first Superboy DC comic book title to appear in publication was Superboy #1 in the Month of March/April in 1949. This was, of course, the pre-crisis Superboy who was also Superman when he was a boy (Kal-El/Clark Kent). The front cover, as clearly seen above, has a child asking Superman what he was like when he was just a boy. The cover art was done by Wayne Boring. Superboy #1 marked Superboy as the sixth DC superhero to have his own comic book title in the DC universe.
The title began as a bi-monthly publication but eventually narrowed releases down to 8/9 issues a year in 1966 to a stable 12 issues a year by 1972 (this is when it became a monthly comic book release). The Superboy pre-crisis title endured 258 issues (total) of publication up until 1977 with Superboy #231 when the title became Superboy and The Legion of Superheroes. A Superboy #1 has been known to sale on ebay for $1,000 US dollars (or more) depending on the condition of the comic book.
The earlier Adventure Comics in which Superboy previously appeared before having his own title, he was about 10 years old. But by Superboy #1 he was in his early teens and most stories revolved around teen plagues and teen romance. Superboy also began to take flight into outerspace in his own title, unlike his relegated earthbound adventures in Adventure Comics. He flew to the moon, intercepted a comet and went back in time in the early Superboy title.
The supporting cast of the young Superman mythos were also developed within the Superboy title (Pete Ross didn't appear until Superboy #86). It should be noted that Pete Ross never appeared in the Superboy TV Series but he did on "Smallville". In Superboy #3 (the front cover is below), Ma and Pa Kent appeared on the front cover and in many more stories. They eventually received names...Jonathan and Martha Kent.
It is within the Superboy stories itself that we actually find the early history between Superman and Lex Luthor and why Luthor hates him. Lex Luthor first appeared with Superboy in Adventure Comics #271 (1960) and it is a classic story; Lex is an intelligent student and friends with Superboy until Superboy puts out a dangerous chemical fire that causes Lex to lose his hair (it also destroyed his experiment). From that day on, Lex is Superboy's enemy. This classic story was also used in Superboy: The TV Series. After Lex lost his hair, he was very upset and demanded revenge.