I intend to setup a t-shirt shop very soon using cafepress.com or a
similar service and would like to include several quotations from
different authors.  What I need to know is this:  Under what
circumstances (if any) is it ok to use quotations on t-shirts which I
intend to sell for a profit?  Is there a difference
between using a quote from someone "long gone" such as the buddha, and
a current author such as Deepak Chopra in terms of legalities?