I don't think there is a problem with doing abs everyday. I personally like ab-work. I think that you can vary the exercises and that way work different muscels in the abs, kwim? Like do ball-work one day, crunches the next, weights the next. Don't know if I am explaining right. There are loads of exercises to work your abs and the different "zones" in your tummy area. By doing different excerises, you can "reach" lots of different "zones". That way you tone the whole area, instead of just the area under your boobs by just doing example crunches.