For new to web design I think it is a very creditable logo, but however if you want to improve it I would maybe suggest that it is a very amateurish logo. It has no depth for starters, it is too "animated". Its a forum, not an animations site, right? The (C) in the bottom corner, as stated, is extremely strange. For starters, its a forum, people can rip whatever the hell they like... its not your work. The logo can't really be copyright because it uses photoshop predefined shapes in it, so therefore isn't acctually your work, and that can be argued as such. The name can't really be copyright, because you own the domain, and also... I could go and make diveplunge.net, and not be worried at all because the only thing that can really protect the name is a trademark.
the register page is the same on every single phpbb forum out on the net at the moment - its neither easy nor hard, but is bearable.
Tom