I mentioned one-point stereo miking in an earlier message,
as a great way to get a beautiful image from an acoustic
guitar.  I often use a $50 AudioTechnica stereo mike, within
inches of the guitar, to great effect.  A better way with
two good mikes is the "mid-side" technique, which gives you
the ability to control the stereo depth during mixdown, and
avoids the phase cancellation effect you can get with A-B
stereo mikes when mixed to mono, coloring the sound in
unintended ways.

Mid-side miking uses two mikes, one pointed at the
sound source ("Mid"), and one pointed to the left or right
("Side").  Ideally, the Side mike is as close to the Mid
mike as possible, and with the element centered directly
above it when capturing a left-to-right image.  The 
Mid mike should be unidirectional (cardioid), and the
Side is best if it has a figure-8 pattern, but I've
only used cardiods -- you'll just lose any highs from
the side it's pointed away from.  Not so good for room
miking, but fine for close miking.

When listening to the mikes during setup, pan the Mid to the
center, pan the Side to the direction the side mike faces,
and pan an inverted copy of the Side the other way.
the source.  [If your mixer doesn't have an invert button,
you'll either need to get an outboard one (are there any?)
or get a nerd to make you one, or else you'll just have to
position the mike "blind", without hearing the stereo effect.
The "cue out" on some cheap old studio mixers, like a Teac 2A,
happens to be inverted.  If you have the schematic for your
mixer, count the triangles (op amps) -- each one inverts.
Any signal path with an odd number of triangles should be
inverted.]

Start with the Mid fader up where you want it, and slowly fade
in the left and right evenly until you get an image you like,
and play with the mike position to get the best sound from.

When recording to n-Track, record the mikes as separate mono
tracks.  (There may be an easier way to do the next steps.)
After recording, duplicate the Side track, and invert one
copy using the invert tool (you'll find it by right clicking
on the toolbar to customize the toolbar -- it may be in the
menus somewhere too but I didn't find it.)  On the two Side
tracks, pan one full left and the other full right.  Send all
three channels to an aux channel, with Mid panned to the center,
and the Sides panned left and right. Set the level for the Sides
to create the amount of image you like.  Apply effects and volume/pan
on the aux channel, as though it was the audio track itself.

For more information on stereo miking, see the following:

  http://www.tape.com/Bartlett_Articles/stereo_microphone_techniques.html 

  http://homerecording.about.com/library/weekly/aa112899a.htm

  http://www.turneraudio.com/tech/stereomic.html