Here is my child swap 101, very unofficial but based on my many years of using the various evolutions of babyswap/childswap most recently in April 2006.
My first advice on baby swap is to tell the CM at the attraction before you enter the line (Fastpass or Standby) that you want to use the swap and find out how they handle it. Do not wait until you are boarding!
The baby/child unable to ride must be with you to do a swap so everyone must approach the line together. Some CM's have you all wait the line together, then the first parent and older child(ren) ride and other parent and younger child wait at the exit and then switch via the exit allowing the older child(ren) to ride with both parents. Off hand I think only Star Tours and Primevil Whirl still do it this way.
Most rides now give you a rider swap pass. The rider swap pass works like a fast pass and allows up to 3 people total to return to that attraction anytime that day so the second parent can ride. You still all enter the standby line or use a FP in the FP line and ask to use parent swap. The CM will give you the swap pass and the parent riding second and the baby (or young child) can then leave to do something else while the first party rides. The second parent then returns to ride via the FP line with the rider swap pass and can bring 2 others along if they like. I prefer the rider swap pass because the baby or child that dosen't meet the height requirement dosen't have to wait the line for something he/she can't ride.
Just to clarify, the purpose of parent swap is to allow a family with a child who dosen't meet the height restriction to enjoy the attraction with only "1 wait", rather than "2 waits" not to expeidate the wait.
Hope this helps!
TJ
It seems that I will be riding it alone and I would appreciate if someone can answer the above question. 
