Information on the Game Boy Advance versions of Mother 1+2 (Mother 2 was released as Earthbound in North America) and Mother 3 is springing up around here like gophers in a Saskatchewan field. Nintendo's latest move is the opening of the official Mother site, which you can find here.
The site is unfortunately only in Japanese, and it has sections devoted to both Mother and Mother 2. Each of these contains a short overview of basic story, character and gameplay elements for their respective games. As a bonus, a short statement from Shigesato Itoi, Mother's producer, is also included, as well as a link to his homepage where he talks about Mother 3!
Mother 1+2 are scheduled for a Japanese release on June 20 while we North American gamers wait in agony for the announcement of localization.