I have heard that also and although I have never had a need to try it out a friend of mine did it and she swears by it. Supposedly they detest the smell and they will run away from it. Problem is they can live in your baseboards and such so if you're driving them out of your bed you're just chasing them to some other place. Your best bet is to just kill them properly.
I wouldn't count on it. Bed bugs can be serious. Make sure you call a professional to get rid of them before you end up with a serious problem. If you need to test for them, contact www.bugsinbeds.com. Keep in mind, bed bugs are attracted to the CO2 that you exhale. It is highly unlikely that a dryer sheet will deter them.