About rest, for me it depends, if I feel like I don't have anymore strenght than I rest for minute longer and reverse.
And when I first saw program I noticed that lack of abs excercises are biggest flaw, so I add them to every work-out.
This program is from the article that Vlatko posted and there is said that the programs like bench/biceps back/triceps and etc are ineffective. I used those programs many times and I had good results, ofcourse they depended on intensity of my workouts. So now I'm thinking should I stick to my old program or try this new one and hope I will get better results.
I'm on that workout for the second week now and I like it very much. It's a lot different from my 3-day split which I used to do before and much harder. Especially when it comes to legs, it's really takes time to get used to get used to it.
But overall if you follow the program as layed out, struggle with as much weight as possible for the given rep/sets range, it will really pump you out after every workout day.
Most of all I like the fact I'm hitting my back and chest twice a week, instead of once every week.
Here's where I found out about that program(only for Balkan people forum):
http://forum.teretana.net/viewtopic.php?t=21865
To je thread koji sam ja otvorio i ekipa mi se stvarno čini da zna šta govori.
I don't like 3 minute rest stuff, I try to rest for 1-2 min. If it's hard I'd lower the reps but I wouldn't change the rest period. I find it more effective.
As for your abs, I think you should do it every day if you don't concentrate on it so much.
That article depends on progressive overload, meaning you add weight every time you accomplish the given rep/set range on a workout day. It's different when you do 6-8 reps with heavier weight as compared to 10-12 with lighter weight. The former requires more energy, that's why you're recommended 2-3 minutes rest, whereas where you have 10-12 reps you're to do 1-2 minutes rest. Nothing is written in stone, it depends on your workout routine.
Doing abs every day is IMO not effective, unless you're on a full body routine. Abs are a body part like any else. If you wanna do abs everyday, you can do your calves, biceps, triceps every day as well. Same thing.