We don't have a profile on myspace, can we participate?

No. You need to be listed in myspace in order to compete. This showdown is only for myspace bands. Its not very difficult to create a profile for your band on myspace. Its going to give you more exposure and many more fans. Even if you don't participate in showdown, you should anyways consider registering your band on myspace.

Go here if you want to know more about how to create a band page on myspace