First, you'll need to find some ringtones you like. To make things as simple as possible, ensure your ringtones are DRM-free MP3 files. Also, they should typically be 30-seconds or less in length.

Once you have some great ringtones on your computer, you're ready to go. Ensure your microSD card is in your HTC myTouch 4G Slide, then connect the phone to your computer using the supplied USB cable. If your HTC myTouch 4G Slide does not mount automatically, touch the USB icon that appears in the menu bar at the top of the display, drag it down to expose the Android Notification Pane, then tap on USB Connected and select Mount (or Disk Drive).

Using a file explorer on your computer, navigate to the root folder (the main directory) of the memory card in your HTC myTouch 4G Slide. Create a new folder called ringtones (some devices require a lowercase "r" so please name the new folder exactly as specified). Now, simply copy all of the MP3 ringtones you want on your HTC myTouch 4G Slide into the new ringtones folder.

That's it! You can now un-mount your HTC myTouch 4G Slide and your ringtones will become available as options when changing your ringtone.

To set one of your new MP3s as your ringtone, tap 'Menu > Settings' from the Home screen. Tap 'Sound', then 'Phone ringtone'. Scroll to the ringtone you want, select it and then tap 'OK'. Congratulations! You just successfully added and changed the ringtone selection on your T-Mobile MyTouch 4G Slide.

See More: Install Ringtones on T-Mobile MyTouch 4G Slide