We saw the launch of the shuttle Endeavour in April 2001. I wrote to Nasa about 3 months before, to request free car passes to park on the Nasa Causeway which is about 6 miles away from the launch pad across the river. There are details about this in Simon Veness's book "A Brit's Guide to Orlando". The address to write to is: NASA Visitor Services
Mail Code : PA-Pass
Kennedy Space Center
Florida 32899
USA
This was of course before Sept. 11th, so I hope they are still allowing people to go on the Causeway. It was a great experience! We parked on the grass near the river. There were tannoys where you could hear the countdown. There were also toilets and some refreshment booths, but we took our own picnic. There were loads of American families there and it was a good atmosphere. Everyone clapped and cheered when the shuttle lifted off! We then went to the Kennedy Visitors' complex, which was great, but everyone else had the same idea and it was packed.
Hope this helps.
Jinny