I usually just use some wet cloth to wipe my bike clean. I thought using the pressure sprayer like below on bikes isn't good. Maybe the pro bikes are more water-resilient?

At the 11th stage of Tour de France this year, after the race, the euskaltel team washed the bikes in front of their motel.

http://www.youtube.com/watch?v=-FSuwwYlN_M
Check the first 15 sec and the section after 2:49.

http://www.youtube.com/watch?v=LiEdIw3jVwM
they didn't use the compressed air much.

(Is there a way to embed video in this forum?)