When I started out using my DSi for audio downloads, I first didn't know how to put music on a DSi at all. After some research on the web, I found that there are actually several options to doing so. Here is what I found:
The simplest way to get music onto your DSi is as easy as it sounds. Simply copy your own music files across and off you go. To do this you need a compatible SD card and software such as iTunes to convert your music to an AAC file version so that you can play it on your DSi.
If you use iTunes then highlight the music files you want to copy (if they are not copy protected), right-click, then select “create AAC version”. This will convert them into a format the DSi player can read. Then copy them across to the SD card (remember to remove the “write protect” tab on the card, if necessary) and then use the SD card in your DSi console.
Another way to put music on a DSi is to download it from an internet site. I personally can highly recommend the DSi Download Center. It is a legal site, which means you will not download unlawful music sites that will infect your pc or console. It is very easy and inexpensive to register. A one off fee of $29.95 will grant you access for six months, an additional amount of $10 will give you a lifetime membership with unlimited downloads.
Both memberships give you access to unlimited downloads which include music, games, movies, media and software. The database is updated on a regular basis and reflects new games whenever they come up. So for a very small investment you can put music on a dsi, and a whole load of other games. It means you can really get the best out of your console.
If you are not sure how to use the site or download and put music on a DSi, then there is an easy to follow tutorial that explains everything. If you are seriously looking into an option to put music on a DSi I would recommend registering with a site like the DSi Download Center – why not check it out?