I have my iphone 3G and I want to start using themes. I'm using a PC and I was told I need a mac to do it? I searched but didn't find anything useful.

I'm wondering if anyone can link me or post steps for the process. Everything I find is in terms I don't understand.

So I'd really appreciate it if anyone can help me out. I also upgraded to 2.1 software yesterday if that helps any.