This also works with the A1200!
One warning: Flash memory has a limited number of writes before failing, and although this number is very large these days it would still be wise to not use it for anything that gets updated frequently (say email data). Or you could just buy an IBM Microdrive (which is a *real* harddisk in CF size), which does not suffer from that problem.
edit: A long time ago I replaced a failing 20MB 2.5inch HD with a 1GB IBM Microdrive in my A1200. You could probably use the space saved (by loosing the big HD) for something else...