You need:

- BSD Subsytem (make sure you have Community Sources installed, you find BSD Subsytem in "System" Categories)
- SUID Lib fix (only if you have 1.1.3 firmware!). You can found it in "Tweaks (1.1.3)" Categories
- HIGHLY RECOMMENDED but not essential : BossTool

Launch the installer, click on Sources

Click on "Edit" and "Add". Enter http://i.danstaface.net

Return to "Categories" (install button) and select "Multimedia"

Select Ringtones, click Install button and ... Welcome! :)

A More complete tutorial is available here : http://www.iclarified.com/entry/index.php?enid=839
Thanks Shalom!