If you’re really really dissatisfied with the crop of ringtones available on the iPhone—what, no chance of grooving to “Baby Got Back”?—then you may be a prime candidate for a controversial new procedure that will let you add your own ringtones.
Concocted by hackers from the #iphone-dev IRC channel, this twenty three step process requires a fair amount of Terminal know how and willingness to risk bricking your iPhone (they claim that nobody has done anything that iTunes’s Restore feature couldn’t fix, but there may be a danger). But when you’re done, you’ll finally be able to use that original Star Trek communicator noise to let all and sundry see that you have the most advanced communication device known to man.
There are also instructions for replacing some of the other system sounds on the phone, if you wish to delve into even deeper realms. I’m hoping we’ll see a GUI interface for this process in the not too distant future or, even better, an officially sanctioned word from Apple on what the heck is up with custom ringtones.
I'm having trouble syncing my iphone or manually adding songs.
There is a MUCH MUCH easier way.
1) Take your favourite MP3 snippet or ringtone and convert it to MP4. (I use Nero Wave Editor to do this, but there are many programs out there).
2) Change the file extension of the .MP4 to .M4R
3) Double click on the file. iTunes will save it in the Ringtones section.
4) Sync your iPhone and PRESTO.
This is the easiest way:
http://docs.info.apple.com/article.html?artnum=307108