Nintendo's rival to the Wii Jog made an appearance in the video shown at this morning press conference, to announce the DSi.
Whereas Wii Jog is, well for the Wii, it seems Nintendo's shot at a wireless pedometer peripheral is for the new DS.
Other little snippets in the video included screen shots from what would appear to be a DSi version of Wii Fit or something similar. It seems the add-on syncs your days activity to the DS wirelessly and logs it, so you can keep track of your weight loss and progress easily.
Nothing official has been announced so we can't tell you when to expect it, but we'll get all in info to you as soon as we have it.