If you missed last year's post, see "We have hummingbirds!".
My mother-in-law spotted a male ruby-breasted hummingbird on 4/21/2008. My wife bought a few replacement feeders that are easier to clean (glass). If you are shopping for a feeder, take it apart and see if you can sweep a rag across ALL of the interior surface. You might need a bottle brush for a few areas, but if you can't see the interior of the base, don't buy it.