A curriculum is a course of study that spans the studentship of the learner. Teachers, schools, districts, or states may develop a curriculum. A curriculum may separate the subjects or combine them into integrated courses. A homeschooler may either subscribe to a curriculum or pursue an eclectic course of study.
Following are links to some curricula of interest.
Virginia Standards of Learning (SOLs) - a state curriculum for K-12 in the main subjects.
Integrating Systems - a middle and high school curriculum that combines subjects.
Rubicon Atlas - Curriculum Mapping (Podcast sessions)
New!! National Standards - the new standards under development for English and math.