Gym Buddy
I took the plunge and traded in for an Iphone a few months back. It has applications for everything, so I searched for one that would work as a workout log.
I found Gymbuddy. I think it cost me $2.99. You can put your workouts and exercises in the way you want to. It has a timer, if you want that, which times between sets. It also has a 1 rep max estimation based on the amount of weight and reps you were doing. I really think this works as well or better than a notebook. It gives summaries of how often you work out, the amount of weight, rep and sets you do and more. You can still listen to your tunes while working out.
If you are an Iphone user and like to log your workouts, this might be something you are interested in.
