Seeing as how DSi is a Japan-only thing at the moment, it shouldn't come as too much of a surprise to learn that DSi Ware download titles are also a Japan-only thing for the time being. To give you a preview of what's to come to the English speaking world some time next year, IGN downloaded and sampled all the DSi Ware games following their Christmas Eve release.
First, a bit of background in case you haven't been keeping up with Nintendo's developments over in Japan. One of the major differences between the DS Lite and the new DSi is that the latter includes an SD card slot and 256 megabytes of built-in flash memory. This allows Nintendo to release WiiWare-style downloadable programs for the system. DSi Ware is the DSi's equivalent of WiiWare, and Christmas Eve saw the start of the service, with 13 Nintendo titles available all at once for download.