who composed the music?
Mark Snow
Smallville
Composer Mark Snow worked with producer Ken Horton to create "Smallville"s score. 
who played superman in the tv series smallville Tom Welling what is it? It is an American superhero television series based on the DC Comics character Superman. for which television channel was it created? It was initially broadcast by The WB, later by The CW.
wiki:17868564
Smallville [SEP] Music
Composer Mark Snow worked with producer Ken Horton to create "Smallville"s score. Snow composed music as he watched the picture, and tweaked his performance when he reviewed his initial recordings. He then sent the music to the producers, who sent it back for recomposition if needed. Individual episodes have their own soundtrack, comprising one (or more) songs. Jennifer Pyken and Madonna Wade-Reed of Daisy Music looked for songs for the soundtrack. Their choices were discussed by the producers, who decided which songs they wanted and secured their rights. Although Snow said it initially seemed odd to combine two types of music on a "typical action-adventure" television show, "the producers seem to like the contrast of the modern songs and the traditional, orchestral approach to the score".