This company offers several affordable options for online curriculum. You can purchase e-textbooks for core subjects in individual grade levels. (These appear a bit dry, but would be a good "spine" to start with.) They also offer two structured online curriculum systems that appear to be flexible and allow a fair amount of control by the parent. All of these options include subscriptions to the Brittanica School Online reference tool and a discount for an online homeschool planning system.
Online, interactive program for learning music reading and theory.
This non-profit organization offers over 100 free self-paced, online, college level courses.
This online math program is designed to help students with math problems (including dyscalculia.)
This hands-on grammar curriculum includes CD ROMs, teacher manuals, and games for learning gramma
Online, super-hero themed science games for elementary and middle school levels.
This program includes videos, worksheets and quizzes for history learning in jr.