I once put one of these: http://tinyurl.com/3eb77 in a '96 Accord (4
door, don't remember the trim level, it came from the factory with power
door locks but no remote entry). It is $39.85, and I did the
installation myself. In addition to the unit, you will need a few
connectors and some wire. This will give you the basic functionality of
remote locking and unlocking and confirmation via flashing parking
lights.

If you add a $0.99 relay, like http://tinyurl.com/34457, you can hook up
the horn to chirp when you lock or unlock the car with the remote. If
you hook up the horn, you can turn it off by programming the unit.

Add another relay, and you can make it so only the driver's door open on
the first press of the unlock button. Press it a second time, and the
rest of the doors unlock. There is already some wiring in the car to
make this an easy feature to implement.

Add a third relay, and the dome light turns on whenever you unlock the
car (it stays on for 30 seconds or until you turn on the ignition,
whichever comes first).

Add a forth relay, and you can get remote trunk release. I did not hook
this up, and I don't remember if the car has an actuator for the trunk.
For this feature to work, you need an actuator for the trunk. If your
manual trunk release is with a pull-lever at the floor, it means you
don't have an actuator. If the manual trunk release is with a button
that you push, you probably do have the actuator.

And, finally, add a fifth relay and you can disable the starter when the
car is locked with the remote. (The diagram in the installation manual
is wrong on how to do this, be aware!).