A search in Google for "visiting Cornwall" or "Cornwall tourist" (that sort of thing) will find a number of web sites.
I did a quick search and found this one
http://www.visitcornwall.com/
p.s. Not sure how you plan to ge there but the roads going down to Cornwall get VERY crowded during August. Because the area gets narrower and narrower the further west you go all the cars get squeezed into fewer and fewer roads.
If you dont NEED to go to Cornwall then Devon or Dorset or Somerset may serve you just as well, without the need to go so far.



