Smart people have figured out how to install homebrew apps on the Palm Pre without rooting the device by emailing themselves .ipk files. PreThinking have put together a nice little video showing exactly how this is done:

How to get the App:

1) Click here to send yourself an email with the link OR Email yourself with this link: http://pimpmypre.com/pmptemp/com.pmp.app.pimpmypresounds.ipk (The app will only install if you open it via the Mail App on the Palm Pre)

2) Open the link from your Palm Pre via the Email App.Your Pre will freeze for a few seconds.

3) You can now find the ‘Pimp My Sounds’ app on the first page of Apps on your Pre.

UPDATE: LINK IS DOWN WHILE A FEW ISSUES ARE FIXED, WILL BE BACK UP SOON.