If spiders like warm and damp, what would making the place cool and dry do? I have a chance to buy a window a/c unit off a friend and it would fit perfectly in my garage window. Would this rid me of a great deal of spiders?

buy an A/C, a dehumidifier, couple cans of spider spray and your set. Just keep up with the sweeping and vaccuming ( but make sure you dont leave the vaccum in the same room your just vaccumed or in ur house ) Also clean out behind cabinets and stuff like that.

If its still legal in your area, get some Diazinon liquid. Mix up a batch in a hose end sprayer or pump spayer and go at the foundation. I do it inside and out and it works for several months. Stay out of the garage for awhile as the fumes are nasty. What Carl said is true. A good treatment outside the garage and even where the garage door comes down will really put a limit on critters getting in the house. A local gardening show in my area recommends spraying up the sides of the outside walls as high as 3 feet. Mike recommended a product I have used inside as well, Home Defense. Good stuff.

Much luck to you SpiderMan!!

Chris