From memory only, so take this with a grain of salt:

Protein Power Phase I - 30 g carb, subtracting fibre

Atkins Induction - 20 g carb, not subtracting fibre

PP: minimum protein requirements, based on size, sex, and activity level

Atkins: none

PP on fat: advocates consumption of unsaturated fats and focuses somewhat on eiconsanoids

Atkins: no suggestions on fat

PP: strongly advocates weightlifting

Atkins: encourages exercise such as walking

HTH