The company announced this morning that the system would go on sale in Australia on April 2nd for an RRP of $299.
The US has to wait an additional three days, although in the US, they'll pay only US$169.99, around $20 less on current conversion rates than Australia. Add US state by state sales tax into that, however, and the differences could evaporate.
The updated DSi is 2.6mm thinner than the DS "lite" model, features two 0.3 megapixel cameras , 3.25" screens (up from 3" on the DS and DS Lite), more brightness settings and claimed improved speakers.
Battery life is said to be a little reduced, but the major other drawback with the DSi is that to keep it thin, the Gameboy Advance slot on the DS/DS Lite is nowhere to be seen, making games such as Guitar Hero: On Tour (and all GBA games) instantly incompatible.