how u do that?? i really want to have the whole east U.S. google street map to be saved in my device...

Well, you display the whole area you want mapped in Maemo Mapper, then there's a place where you specify which zoom levels you want to save. Of course, you have to have a sdhc card which will hold all the data, and that would be a lot for the whole eastern US.

My description is vague because it is so easy I don't remember exactly how I've done it -- there are a lot of wonderful Maemo Mapper threads out there, and the help system that goes with Maemo Mapper is pretty good as well.