Or you could just take the MIT OpenCourseWare class http://ocw.mit.edu/OcwWeb/Electrical-Engineering-and-Compute... (uses Scheme also)
Both HTDP and conabs inherit their methodologies from SICP. (in htdp you could even look at The Structure and Interpretation of the Computer Science Curriculum here http://www.cs.brown.edu/~sk/Publications/Papers/Published/ff...)
But it is worth to look at the same thing from different points of view. As Alan Kay says, it is worth 80 IQ points :)