The Lightning Thief by Rick Riordan

Percy Jackson is a good kid, but he can’t seem to focus on his schoolwork or control his temper. And lately, being away at boarding school is only getting worse-Percy could have sworn his pre-algebra teacher turned into a monster and tried to kill him. When Percy’s mom finds out, she knows it’s time that he knew the truth about where he came from, and that he go to the one place he’ll be safe. She sends Percy to Camp Half Blood, a summer camp for demigods (on Long Island), where he learns that the father he never knew is Poseidon, God of the Sea. Soon a mystery unfolds and together with his friends — one a satyr and the other the demigod daughter of Athena — Percy sets out on a quest across the United States to reach the gates of the Underworld (located in a recording studio in Hollywood) and prevent a catastrophic war between the gods. (Barnes and Noble)

This is the first in the Percy Jackson and the Olympiand series.  There are 4 books out now, and one more on the way later this year to complete the series.

Book 2: The Sea of Monsters

Book 3: The Titan’s Curse

Book 4: The Battle of the Labyrinth

Book 5: The Last Olympian (Due Out in May 2009)