In case you were wondering.

“DSi software (software that is only compatible with DSi) is region locked, eg: European DSi software can only be played on European DSi consoles,” a Nintendo spokesperson has told CVG.

“Nintendo DS software however is region free so you can play any DS software on DSi from any region. You can also browse the Internet on your DSi wherever you are in the world and exchange your photos with friends from around the world.”

“DSi is region locked because DSi embeds net communication functionality within itself and we are intending to provide net services specifically tailored for each region. Also because we are including parental control functionality for Nintendo DSi and each region has its unique age limit made by different independent.”