Going through the schedule, it looks like HD customers will be affected first with many becoming MPEG-4 stations during the first phase. SD only customers will start being affected in the second phase.
The other thing I noticed is it looks like Shaw will be giving up some transponders on Anik F1R and F2. Shaw Direct/Broadcast currently occupies 30 transponders on Anik F1R. After the transition it will be down to 25. For Anik F2 they will go from 22 to 6. Some space will also clear up on Anik G1 with the removal of some duplicate SD services and the migration of Vancouver HD signals over to Anik F1R.