To the OP - pressure washing works wonders on concrete although even with cleaning it with pressurized water it would be a good idea to add a bleach mixture to kill the mold that can remain even if it looks clean.
Speaking of cracking up! Hey Jaybee, I've been sealing concrete with great results...a product called Seal-once. check it out on google...makes the surface waterproof, but allows it to breath...prevents moisture build up...prevents freeze thaw damage/cracks...