Not much different from any other car, except for one thing.  To replace
the PS belt, a hose must be removed from the manifold that goes around the
top of the engine compartment.  So you need to be prepared to do that- new
clamp, new length of hose if necessary.  But the BIG thing to be careful of
is this- very often you find that once removed, the hose must be replaced. 
The fitting at the top is no problem, but the fitting that came as original
equipment on the right head is plastic and very easily broken.  If broken,
a replacement often must be ordered.  The fitting sold as a replacement is
metal (much improved design) and many vanagons have already had this
repalcement done.  And the plastic one can be saved if one is careful- you
just have to be aware of the problem potential.

I learned all this the hard way.  I once decided to change my belts on the
Friday night before starting a weeklong vacation trip.  Not knowing the
potential problem, I broke the plastic fitting when I replaced the hose. 
With no way to get a replacement before Monday (at least) I almost had to
cancel my vacation trip but was saved by a listmember who TOOK THE FITTING
OFF HIS VAN and loaned it to me for my trip.  Now there was a nice guy, and
a clear demonstration of the power of the list.

Bill
St. Louis, MO
www.geocities.com/yosemite/gorge/1706