Saving yeast saves me tons of money! I have several strains in the fridge right now, and really like reusing it.
There are some better techniques than just scooping it out and saving it, though. You want to get rid of the trub (which can cause some off-flavors) and keep only the yeast. You always want to be not just sanitary, but overly so, if that makes sense. Take a look at this thread: http://www.homebrewtalk.com/f13/yeas...strated-41768/
that will really help with yeast washing and saving.