Yes. There is. Just google "nokia theme creator"!
But bewarned: it' quite a BIG programme and not exactly intuitive - take a couple of days off, cancel all appointments, etc... If you have s60 3rd ed. phone, you can get "diy theme", installs right on your phone. Not fancy, but enough to keep you happy...
Hi Jdcruz,
Why bother just go http://symbian.mobilethemes.com/ there are literally hundreds of themes for all the different Os's listed in specific OS categories and some if not most of them are excellent IMO.