Note: For those WITHOUT internet. This method works well on my Treo 600, with Blazer Web Browser v3.0.
To incorporate MIDIs on your SD card into your palm's ringer/alarm sound database:
1. Save the midi file (must be smaller than 64KB) on your SD card (via card reader) at an easy to remember location (e.g. F://midi/usher.mid)
2. Stick the SD card into your Treo.
3. Fire up Blazer (a.k.a. "Web" in your Launcher). You DO NOT have to connect to the internet, so hit cancel if it does so automatically.
4. Access the "Go To" Dialogue (3 ways of doing this: click the (www) button, go to Menu/Go/Go to Web Page, or use shortcut /G).
5. Enter the following for the URL, replacing the [ ] accordingly:
file:///[directory]/[filename].mid
(for the earlier example, i would enter "file:///midi/usher.mid")
*note: the url is not case sensitive, but whatever case you type in now will be the filename when you want to save it later. Save yourself a step by using proper casing.
6. Hit [Enter]. If it begins to connect to the internet automatically, hit cancel.
7. Ignore the Download Warning dialogue pops up warning about the size of the midi by hitting [Yes]. (i think Blazer has problems detecting size of items on your SD card)
8. Hit [Yes] for the Download dialogue box.
9. Hit [Save] after the download is completed (which should take only a second or so).
10. Format the filename as you wish. Spaces are allowed between words, and there is no need to include ".mid".
11. Voila! The midi file is now incorporate into your system sounds. Check it out by running the Sounds program on your launcher.