For both of you that clicked on this post:

http://www.panix.com/~jens/morse.par

is a very interesting page I came across while searching for this exact solution. It's even slightly professional--having all of my military friends come up in fast-paced Morse Code for their ringers. Rest assured that very few people will even know what's being played. If you haven't noticed already, a lot of cell phones out there play ... -- ... (SMS) when a message arrives. Now you can create a MIDI for just about anything you'd like.

Simply go to the link, and put in your text. Change the tempo if desired, and play. You can probably do a 'save as', or you can have it save the file as opposed to playing it.

From there, to make it more Treo600 compatible, I took PSMPlayer and Anvil Studio to crank up the volume, and occasionally I feel like changing the instrument for more of a sharp instrument as opposed to a flutey instrument.

To make things even cooler, and a whole lot easier--visit the page directly with your phone! Put your text in, choose the tempo, and have it 'attempt to play immediately'. This will send the MIDI to your phone, defaultly 'ascii2morsemidi.cgi'. Save it. Perhaps change the name. Oddly enough it shows up in your tones! Even better? It's pretty darned loud as it is. I haven't done any side-by-side comparisons.

I wrote the gentleman with the page, and he has no problem with us taking and using his source code. He also says for now he doesn't mind huge numbers of several K downloads.

Have fun!