I have seen many threads asking how to put custom ringtones on this phone, so I'm going to post a guide to solve the problem once and for all.

Some of the details may be specific to the Bell A920, but it should work for the Sprint A920 as well.

If I have missed anything, please tell me.

Part One: Convert the Files

The A920 can use mp3, m4a, aac, and qcp files as ringtones.

Don't use qcp files as they are really low quality, especially for anything with lots of bass, and the A920 can do better.

I recommend using m4a files as it keeps the size down.

To create a ringtone, you should cut it to about 30 seconds because you phone usually won't ring longer then 30 seconds.

If you have Nero on you computer, use Nero Wave Editor, otherwise download Audacity as it's free. Nero comes with a lot of CD and DVD burners and may already be installed if you computer came with a burner.

Use the audio editor to cut the file to 30 seconds, and save it as an m4a.

Part Two: Getting the Ringtone(s) To Your Phone

To get the ringtone onto your phone, you have two options:
Use an uploader, or use the data cable that came with your phone. Bluetooth is not an option as neither Bell nor Sprint allow full OBEX on their phones.

Option One: Using an Uploader

An uploader is a website where you upload the file and give your phone number, then the site sends a message to your phone with a link to the file attached. This is the easy way, and the way that you should do it if you have unlimited browser. The only downside is the cost of unlimited browser. I do not recommend using an uploader if you don't have a browser plan as the fees will be extremely high.

I haven't used this method because I don't have unlimited browser, but it is covered in other threads and if you are still not sure post and someone will help you.

Option Two: Using the Data Cable

BitPim cannot be used with the A920 as of yet. If someone finds a setting that works, don't be afraid to post it.

If you are really comfortable with technology or don't mind following instructions to the letter, check out this guide on using the data cable:
Samsung A920 Data Cable Guide from 3ginferno

NOTE: Certain parts of the guide use tools that can seriously damage your phone. I am not responsible if you damage your phone using the information in the guide. Also, I did not write that guide, I am only providing the link to it.