Same problem in our house. It's over a hundred years old with a stone foundation. We have a veritable river running down there as long as the temps are above freezing.

I don't like the idea of sealing from the inside. This means that water is allowed to infiltrate the foundation walls right up to the interior surface. I'm thinking that the water would then want to flow vertically through the wall, weakening it further. Also, freezing and thawing would be a problem.

The ultimate for our situation (besides having gutters in good condition) would be to dig around the walls right down to the foundation. Seal the exterior with something (there's quite an array of products to choose from); backfill with a little gravel; lay down drain tile; landscape cloth on top; more gravel; and finally backfill. There are several additions (front porch, rear deck, and lean-to) that would have to removed to accomplish this. I don't have the resources (read cash) for this type of fix right now.

My plan, as I've seen down in many farm houses in the area, is to control the water that does get in. I'll be chipping a small trench in the floor around the foundation walls eventually leading to the sump pit. Having a thinner, deeper channel of water would seem to evaporate less readily than having it spread out in a thin layer across the whole floor.