Dmi,
From offhand:
1. Disconnect negative battery terminal
2. Remove the passenger side kick panel (4 screws)
3. Remove the little lamp under the dash on the passenger side
4. The ECM is hold by one hex head screw, unscrew it and you can drop your ECM. It could be tight, but it should come out
To put it back I usualy remove the speaker grill and the speaker. This way you can help to manouver it into the right place from above.
HTH,