It’s not new that you can create custom ringtones for your iPhone, it is however new that you can use these ringtones for messaging. In iOS5 all the ringtones on your phone are available to set for things like
- Incoming SMS messages
- Incoming iMessages
- Read receipts from iMessages

So get creating! Our post from 2009 is still the business for the quick and free way to make ringtones for iOS5, using Garageband on your Mac.
Alternatively, the iTunes store on your iPhone now has a section where you can buy ringtones, although coughing up the same price as a whole song for a short sound bite may keep you away from too many of these. The store pictured here is loaded up with many good Star Wars tones; who doesn’t want Darth breathing at you when you receive a text message?