H&C products work well. I've used them in the past.

I've also heard good things about..... Concrete Sealer X-1 is a permanent silicate based deep penetrating sealer which means that it is guaranteed to last for the life of your concrete because it chemically bonds to the concrete to become part of its integral structure. It is highly effective in making concrete physically stronger and denser protecting it against frost and salt while increasing its resistance to stains, acids, alkalis, moisture, mold and mildew. This product will cure damp and wet basements by preventing hydrostatic water from penetrating through the concrete. It will also stop dusting, efflorescence, spalling, pitting, crumbling and prevent mold, mildew and algae growth. The product will seal the concrete to significantly reduce the level of radon gas penetration which is known to cause lung cancer by the EPA.