Here's a good online article about how to make them. You may also find better Crackberry help if you post your question in the Blackberry Developer's forum. But this website, where the article is from, has several good reference articles on how to creates themes.
Thanks for the info about the link and being able to get the access to build our own themes!! I am downloading the blackberry theme studio 5.0 now. It's a large file, I am using my satellite internet so hopefully it will not take all day. I am looking forward to this and then searching around blackberry developement site for more.