Well, the main problem with MySpace is when people give out too much information. Such as name, school, address, email, phone, IM names, etc.
It can be used safely as long as you don't post this kind of info and I wouldn't post any pics of yourself either. Especially for a minor.
There are things that you can do to protect yourself more too.
There are Privacy settings:
Check "Require email or last name to add me as a friend" if you want other users to be required to know your email address or your last name in order to send you an add friend request (this prevents people who don't know you from trying to add you as a friend).
Check "Approve Comments before Posting" if you want to review comments to your profile and journals before they are posted. Comments will NOT appear unless and until you approve them.
Check "Hide Online Now" to make your online status invisible to other users.
Check "Show My Birthday to my Friends" to alert your friends when your birthday is near.
Which I would not do.
Check "No Pic Forwarding" to prevent other users from emailing links to your images from the site.
Check "Friend Only Journal Comments" to allow only your friends to post comments on your blog entries.
Check "Block Friend Request From Bands" to block unwanted friend request from bands.
Which might be a good idea too.
There are also IM Privacy settings.
For any of these security settings to apply you must have "Hide Online Now" unchecked from the Privacy Settings page.
Check "No one can IM me" if you want to prevent anyone from sending you an IM request.
Check "Only Friends can IM me" if you want to prevent anyone that is not your friend from sending you an IM request.
Check "Anyone can IM me" if you want to allow any user to IM you.
Links to My Space are not allowed on the DIS
Hope this helps.
FYI: I have an account there.
Oh. Another tip. Before registering, create a free email account someplace (hotmail, yahoo, etc) that is different from your normal one. And use this one only for MySpace. This way, it's harder for anyone to actually find you if there is ever a "break-in" for the info on MySpace servers.