iSkin has iPhone 4 cases coming (rumored to be in limited stores). They sure look cool on the iSkin site.
For a limited time, you can give them your thoughts and get an email when the new iSkins are available. By signing up though, you are signing up to get their ‘other’ emails too. To make it worth your time, 10 subscribers will get a free iSkin case.
If you accept getting emails from a company with great products, then that isn’t really spam, right? There is a fine line between too many marketing/newsletter emails and just enough that a person doesn’t mind getting the updates from time to time.