There are reports floating around that you will indeed be able to download game demos via the Wii’s online service, WiiConnect24. None of this has been confirmed, so take it with a grain of salt, but there has been a roughly translated bit of information taken from a German Wii page which leads to the possibility of downloadable demos.

Information Inside

From a German Wii Page – i translated it quick with google..

Original:
Quote:
Enthllt: Wii-Demos als Download
Wii-Besitzer mit Internet-Anschluss werden sich Demoversionen von Wii-Spielen herunterladen knnen.

Die Vermutung gab es schon lnger, jetzt ist es offiziell: Neben Virtual-Console-Spielen werden Wii-Fans mit Internetzugang auch Demoversionen von Wii-Titeln herunterladen knnen. Die Demos kann man dann entweder im 512 MB groen Flashspeicher der Konsole oder auf einer separat erhltlichen SD-Karte speichern. Welche Demos den Anfang machen, will Nintendo in Krze bekannt geben.

Translated:
Quote:
Revealed: Wii demo as Download Wii owners with Internet connection will be able themselves to download demo versions of Wii plays. The assumption gave it already longer, now is official it: Apart from Virtual CONSOLE plays Wii fans with Internet entrance will be able to download also demo versions of Wii titles. One can store the demos then either in 512 MT the large Flashram of the console or on a separately available SD-map. Which demos make the beginning, Nintendo wants shortly admits to give.

Now remember, this isn’t confirmed because there isn’t any way to really validate how credible the source is, but we can only hope that it is indeed true.

Source: GoNintendo