I don't so much have a procedure to replace the bushes but I think I can still remember how to do it. There was nothing particularly hard about it it was just time consuming, probably because all the bolts seemed to rust which didn't make things easy for me. If I was going doing it again I'd unbolt the front wheels and spray all the ends of all the nuts and bolts that you think will need to come off with WD40. Bolt back on the wheels and come back to it a few days later.
Going off memory (which could be fuzzy) jack both sides of the car, unbolt the wheels, unbolt lower shock mounts, separate the lower wishbone, unbolt the front anti roll bar drop links, loosen (do not remove) the bolts for the front subframe to allow it to drop, unbolt the anti roll bar mounts and remove the bushes. The mounts were soaked in WD40 for a few days and still fought me all the way, so a wire brush and WD40 a few days previous comes highly recommended.
Reassemble in reverse, using a torque wrench, and get car re-tracked. I'll be back under the front of my 156 next weekend as I've knocking starting again somewhere so I've to investigate. If you have any questions I should be able to help more then when I familiarize myself with the Alfas front suspension again.
Hope this helps a bit.