Installing 10.1.3 to SD Card/USB Stick

[Chris Marshall]

I would like to try installing 10.1.3 to
an external SD card (the slot) or a USB
pen drive.  The directions from the wiki:

  http://wiki.laptop.org/go/Installing_to_SD_Card

say to use the ext3 image format file but
there don't appear to be any of those being
generated with the candidate osXXX.img files.

Are the .usb files a new name for the ext3
image files?

Thanks much,
Chris