MP3 is the preferred file type for the Dare, and for most Verizon phones.
There are a couple of ways to get ringtones to your phone.
1) Purchase a membership at freeringers.net. It is $8 for the first year and I think $12 a year there after (you get the first 4 months free). You can send unlimited ringtones and pictures to 4 phone numbers. Choose your other 3 carefully, as you cannot change phone numbers that you have already entered. You can however, change the type of phone for each number, so if they upgrade, it does not become useless. I currently have the LG Dare, and use this method to send the files I create from Magix Ringtone Maker to my phone.
2) Download BitPim. This program allows you to see all the hidden folders on your phone that normally you are prevented from seeing for the sole purpose of preventing you from getting ringtones and other items onto your phone without paying Verizon for them.
Now, I have not attempted to do this yet, but you can google BitPim LG Dare, and I found a person who claims to have made it work for the Dare. This program is open source (free), but you may have to find help to make it work for the Dare.
Option #1 is guaranteed to work. However, every once in a while, Verizon finds a way to block the messages that are sent from the site. Simply contact their technical support and they will help you get around it. They are extremely helpful.