-- Eject the USB drive, put the SD card back into the R4. Power on, open up Moonshell, and pick a song!

-- For more information on DS homebrew and storage devices, visit the Nintendo DS Homebrew Wikipedia page.

As for upgrading from my DS Lite, I reserve final judgment for when the DSi is officially released in the US. But currently, the new changes aren't terribly compelling. For starters, DSi will have a shorter battery life compared to DS Lite and will sell for a higher price- US$179 as opposed to $129. Finally, the DSi will no longer be compatible with Slot-2 games or devices, such as GBA games or Guitar Hero: On Tour.