That is an interesting question. To me, I would probably say there is not a need for one, but of course others who may have looked into this can chime in.
If you mean a disc clean-up type utility similar to Windows, ie. getting rid of temp files, browsing history etc. I would say iOS would most of that for you. I'm not aware of temp files existing in iOS, and browsing history can be easily cleaned in Safari settings.
Content is easily managed via iTunes sync, so is space is getting low, you can choose to remove some apps, music, videos, or pictures easily enough.
Programs can be cleared from memory via the multitask bar by double clicking the home button and holding the icons until they wiggle and press the red button to remove your selected apps from memory.
I guess the question in the end is what is it you want to clean?