Waterproofing?
 

I have a Nike Climafit jacket that is great for wind protection and used to work awesome against rain, it could be pouring buckets out and the water would just bead off. However, I went for a rain the other day in the rain and it just soaked right in, is there some kind of spray that I can use to rejuvenate it's rain repelency?

Nikwax? This is a DWR over waterproof membrane, correct?

http://test.ebrasingtons.com/CleaningGear.html

Does the garment have care instructions handy?

no, it's just a polyester windbreaker

I have a Nashbar wind shell that I decided to experiment with. I got a can of Coleman Heavy Duty water repellent. Works good. I treat it once a year after having washed the shell several times.

"Waterproof-breathable" fabrics will not work if water does not bead on the surface. I have had good luck with Nikwax. Are the seams taped? If not, you may need to seal them with something like "Seamgrip" or "Aquaseal".