See my reply to this identical message in rec.autos.makers.honda.

Learn to crosspost correctly so that all me benefit from this thread.

It helps to have the new one in your hand when you're on the
left side of the dash, near the driver's usual knee
location, trying to spot it. Alternatively, maybe the
pictures and photos at the  following sites will help:

http://techauto.te.funpic.org/civicrelay.php

http://www.marklamond.co.uk/tech-honda/pgm-fi/main-relay/main-relay.htm

http://www.tegger.com/hondafaq/mainrelay.html

Lot of folks say just pulling the guts of the main relay
out, and leaving the outer casing bracketed in place, makes
life easier.

The dash does not come apart for this. You just have to
reach somewhat up under it. Kinda tricky to get out, but
plenty of do-it-yourselfers and rookies have succeeded at
it.

Above the driver's knees - IIRC there is a module to remove from underneath
it. As Elle says - a bit frustrating but I've done worse. It really is
easier to pull the guts out of the relay, because those mounting nuts
(bolts?) are even less accessible than everything that comes before.

Mike