Try looking through the themes that already exist (http://forums.crackberry.com/f131/). Personally, I've always found themes to be problematic on the Storm, but I'm sure there are some better ones out there.
Theres a small problem with downloading themes from crackberry web page. I am in Latvia and latvian carriers do not support blackberry prones at all. So i can't get ServiceBook file to get back my browser and mms icons. That's the reason why I can't download OTA files. I will be glad if You will be able to give me some advices about my problem. By the way, I already tryed method that posted on that forums - replace servicebook file from another carrier.