Is there a database on the web where you can look up places (for example by city or county) that are willing to rent kitchen space, preferably by the hour? Or what's the best way to go about finding space for a new buisness?

You can try here: http://www.commercialkitchenforrent.com/

Googling for the name of the county in quotes (or the city/metro area name) along with "commercial kitchen rental" or "kitchen incubator" might also come up with some good results.

I will check out the site.