How can I avoid notes to be deleted from the iPhone when I delete them on my Mac Email app? Since the last software update on my iPhone 3 all the notes that I writte on the iPhone appears in the mail.app on my mac as income mails. 

When I delete the notes at the Mail.app, they are also deleted at the iPhone. 

Do you know how to avoid the notes to be deleted?

Thanks!
Turn off notes sync in Settings -> Mail,Calender,Contacts -> select your account and then turn off notes sync.

In Mail if you hit command + comma you can also stop showing notes in the inbox.