I did mine using this method:
http://www.toyota-4runner.org/4th-gen-t4rs/176877-power-steering-hose-size.html
I did it by myself and used just over a litre of fluid. We later did the same on my cousin's Tacoma and did it together and used less than a litre of fluid because I could actually see when the clear fluid started coming out.
The fluid I used was synthetic Castrol fluid. The bottle looked something like this (not exactly though):
If I had a Toyota dealership near me, I would probably garb original Toyota transmission fluid from them.
P.S. When doing the flush on the Tacoma we were in a rush and I did not pay attention to what was going on with the hose that went to the oil drain pan. That was a mistake because somehow the hose jumped out from the pan at the very beginning and
all of the drained fluid ended up on my driveway, lol. There is still a huge spot on the driveway, but it did give us some good laughs when it happened.
Edit: I should also note that it takes only about 10-15 minutes to do this.