Richard's answer is (sadly) as full of holes as a colander!
First,you would be lieing if you tried to say that you had not been part of a discipliary process,you are already by being suspended.
Secondly,it is very little hassle to a company to have such a hearing,especially given that you have already admitted the theft.
Thirdly,it is VERY unlikely (as I said before) that you can leave with the clean sheet Richard says you may,It will only stay clean for as long as a new employer looks into the reason that you have resigned.
If you lie and give a false reason for your resignation (and a new employer WILL ask believe me),that will be found out,and if you say you were dismissed then the same scenario will happen.
It is probably better to be honest with any new employer and hope they will feel sympathetic.
Lie and you will fall at the first hurdle.