As you problably just want to play games, you would want an Acekard 2i. It´s a great flashcart and it does the job. You would want to order it from
Shoptemp. If you dont have an extra DS Lite or DSi with 1.3 firmware, you would wanna add in
Shoptemp Acekard 2i site. Premium Flashing Service, so that it comes pre-flashed for DSi XL 1.4 firmware (which is the one your DSi XL has), you may also want to add an micro sd ( I suggest 4 GB), so if you select Premium Flashing, you can play straight out odf the box (but remember you have to download the Backups(GAMES) that you want and copy them to your micro sd).
You may also want to try the
SuperCard DS Two, whict is the newest flashcart, and includes Almost Perfect DS Games Compability, Real Time Save( so that you cand save it whenever you want), Real Time Guide( so you can view guides and walkthroughs while playing the game, Snes Emulator, GBA Emulator, Divx/Xvid and other video formats playback, an E-Book Reader, and beautiful GUI,and more features that have not been announced.And, it also comes preflashed for 1.4.
If you order the Acekard 2i you may wanna follow this
guide made by TK_Saturn, if you get confused or something.
Hope you enjoy it.
Naruses