Not to bump down Doc's awesome Sonic post (seriously, check it out, it's right down there), but the HeartGold/SoulSilver website is now open. Check it out here. Nothing we didn't already know on it, but the art is nice, and it looks from one of the screenshots that the Itemfinder is now the Dowsing Machine, as it was in Diamond, Pearl, and Platinum - or, at least it is in the Pokewalker.
Incidentally, the confirmation of the Dowsing Machine's name confirms at least one item on Serebii's list of English names. The names have yet to be confirmed in any official capacity, but if you like, you can check them out here. The only other name on there confirmed is the female playable character's name - Kotone is now known as Lyra. Kotone's name comes from a string instrument, as does Lyra's. Pokemon.com confirmed that name here.
In other HG/SS news, it looks like the slot machine minigame, present in all versions of Pokemon until DPP (where they were taken out of the European release), will be removed from English releases. It will instead be replaced by a minigame named Voltorb Flip, which is described by Official Nintendo Magazine as a cross between Minesweeper and Picross. Their review covers the game in more detail. ONM notes that they were playing the UK version, but they also repeatedly say the game is in the English-language version of the game. So take it as you will.